Arizona has been affected by hurricanes on numerous occasions. Usually, these storms originate in the eastern Pacific Ocean, make landfall in the Mexican states of Baja California or Sonora, and dissipate before crossing into the United States. Thus, in most cases, it is only the tropical cyclones' remnant moisture that produces heavy rainfall—and in some occasions, flooding—in portions of Arizona. However, approximately every five years, a tropical cyclone retains sufficient strength to enter the state as a tropical storm or a tropical depression. Arizonans can expect indirect flash floods caused by the remnants of tropical cyclones to occur about every two years.
Arizona is a state in the southwestern region of the United States. It is also part of the Western and the Mountain states. It is the sixth largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona shares the Four Corners region with Utah, Colorado, and New Mexico; its other neighboring states are Nevada and California to the west and the Mexican states of Sonora and Baja California to the south and southwest.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".
Mexico, officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometres (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the eleventh most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.
Tropical cyclones in Arizona are not common, since the predominant wind pattern steers most storms that form in the Eastern Pacific either parallel or away from the Pacific coast of northwestern Mexico. As a result, most storms that could affect Arizona are carried away from the United States, with only 6% of all Pacific hurricanes entering US territory. Not all Arizona hurricanes originate from the Pacific Ocean, however; in July 2008 an Atlantic hurricane named Hurricane Dolly produced rainfall in the eastern portion of the state, and another Atlantic storm reached Arizona as a tropical depression. Many, but not all, of these systems also impacted California.
An Atlantic hurricane or tropical storm is a tropical cyclone that forms in the Atlantic Ocean, usually between the months of June and November. A hurricane differs from a cyclone or typhoon only on the basis of location. A hurricane is a storm that occurs in the Atlantic Ocean and northeastern Pacific Ocean, a typhoon occurs in the northwestern Pacific Ocean, and a cyclone occurs in the south Pacific or Indian Ocean.
Hurricane Dolly was a strong tropical cyclone that made landfall in Deep South Texas in July 2008. Dolly was the fourth tropical cyclone and second hurricane to form during the 2008 Atlantic hurricane season. Dolly developed on July 20 from an area of disturbed weather in association with a strong tropical wave. It was named at the same time it formed—skipping the tropical depression phase entirely as the precursor wave already had tropical storm-force winds. This marked the earliest time a fourth named cyclone formed since the 2005 season, which used to hold the record until it was surpassed by the 2012 season and then by the 2016 season.
Despite their rarity, hurricanes are among Arizona's most significant weather makers. In years when Arizona is affected by a tropical cyclone, these can be responsible for up to 25% of the rainfall in areas along the Colorado River. Arizona hurricanes are also responsible for torrential rains in localized areas, with the state's 24-hour rainfall record—11.97 inches (304mm) of precipitation—occurring during Hurricane Nora's landfall in 1997. The heavy rainfall can trigger extensive flash floods, such as the ones produced by the remnants of Tropical Storm Octave in 1983, or the lingering moisture from Tropical Storm Emilia in 2006.
The Colorado River is one of the principal rivers in the Southwestern United States and northern Mexico. The 1,450-mile-long (2,330 km) river drains an expansive, arid watershed that encompasses parts of seven U.S. and two Mexican states. Starting in the central Rocky Mountains of Colorado, the river flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the international border. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora.
Hurricane Nora was only the third tropical cyclone on record to reach Arizona as a tropical storm, and one of the rare cyclones to make landfall in Baja California. Nora was the fourteenth named tropical cyclone and seventh hurricane of the 1997 Pacific hurricane season. The September storm formed off the Pacific coast of Mexico, and aided by waters warmed by the 1997–98 El Niño event, eventually peaked at Category 4 intensity on the Saffir–Simpson hurricane scale.
Tropical Storm Emilia was a rare tropical cyclone that affected the Baja California peninsula in July 2006. The sixth tropical depression and fifth tropical storm of the 2006 Pacific hurricane season, it developed on July 21 about 400 miles (650 km) off the coast of Mexico. It moved northward toward the coast, reaching peak winds of 65 mph (105 km/h) before turning westward and encountering unfavorable conditions. Emilia later turned to the north, passing near Baja California as a strong tropical storm. Subsequently, the storm moved further away from the coast, and on July 27 it dissipated.
Number of storms affecting Arizona
Number of storms
Tropical cyclones are not common over Arizona, but on average, a tropical storm or a tropical depression enters the state approximately every five years. However, indirect flash floods caused by the remnants of tropical cyclones are more common, as they tend to occur about every two years.
A flash flood is a rapid flooding of low-lying areas: washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a severe thunderstorm, hurricane, tropical storm, or meltwater from ice or snow flowing over ice sheets or snowfields. Flash floods may occur after the collapse of a natural ice or debris dam, or a human structure such as a man-made dam, as occurred before the Johnstown Flood of 1889. Flash floods are distinguished from regular floods by having a timescale of fewer than six hours between rainfall and the onset of flooding. The water that is temporarily available is often used by plants with rapid germination and short growth cycles and by specially adapted animal life.
Storms that approach the southwestern United States, and by extension Arizona, generally form closer to the Mexican shoreline than average, making them more likely to recurve northwards under the influence of an approaching trough. These troughs tend to extend farther to the south during the latter part of the Pacific hurricane season, in the period between late August and early October. These pronounced troughs thus produce a synoptic-scale flow that is conducive to steering hurricanes towards the southwestern United States.
A trough is an elongated (extended) region of relatively low atmospheric pressure, often associated with fronts. Troughs may be at the surface, or aloft, or both under various conditions. Most troughs bring clouds, showers, and a wind shift, particularly following the passage of the trough. This results from convergence or "squeezing" which forces lifting of moist air behind the trough line.
The infusions of tropical moisture from Arizona-bound tropical cyclones can be a significant portion of the rainfall in the region. In years when hurricanes approach Arizona, eastern and northern portions of the state receive on average 6–8% of the monsoon-season precipitation from tropical systems and their remnants. This percentage rises towards the southwestern corner of the state, which can receive up to a quarter of its monsoon-season rainfall from tropical cyclones.
The North American monsoon, variously known as the Southwest monsoon, the Mexican monsoon, the New Mexican monsoon, or the Arizona monsoon, is a pattern of pronounced increase in thunderstorms and rainfall over large areas of the southwestern United States and northwestern Mexico, typically occurring between July and mid September. During the monsoon, thunderstorms are fueled by daytime heating and build up during the late afternoon-early evening. Typically, these storms dissipate by late night, and the next day starts out fair, with the cycle repeating daily. The monsoon typically loses its energy by mid-September when drier and cooler conditions are reestablished over the region. Geographically, the North American monsoon precipitation region is centered over the Sierra Madre Occidental in the Mexican states of Sinaloa, Durango, Sonora and Chihuahua.
Tropical storms are one of Arizona's main sources of rainfall, as they infuse the monsoon over the southwestern United States with moisture, producing large-scale floods in occasions. However, all of the storms that have impacted Arizona have formed in the latter parts of the Pacific hurricane season, and only storm remnants have affected the state before August.
August 1921: The first known tropical disturbance to affect the state occurred when a remnant low of a tropical cyclone moved into the western portions of the state.
September 1921: A tropical depression that had tracked parallel to the Mexican coastline moved into Arizona, causing heavy rainfall on September 30. This tropical storm caused more than three inches of rainfall along the Colorado River valley, with 3.65 inches (93mm) of rain reported in Yuma. Throughout the state, Flagstaff saw 1.50 inches (38mm) of rainfall, while 1.24 inches (31mm) of precipitation fell in Prescott, 0.68 inches (17mm) in Tucson, and 0.56 inches (14mm) in Phoenix.
September 1926: Five years later, the remnants of another September storm hit the state, but this time the precipitation was heaviest on the southeastern portion of the state. The 1926 storm caused over 5.00 inches (127mm) of rain in the vicinity of Douglas.
September 1927: The remnants of another tropical system caused 1–2 inches (25–51mm) of rainfall throughout the state.
August 1935: The remnants of an unnamed tropical storm that landed on Southern California caused torrential rain and flooding across Arizona, especially along the Santa Cruz River and Rillito Creek on Southern Arizona. The rainfall from the storm contributed to an extremely wet month of August, which still holds the monthly rainfall record at the National Weather Service office in Tucson, as 5.61 inches (142mm) of rainfall fell during the month.
September 1939: Two tropical systems entered the state during the month. On September 4, the remnants of a former hurricane entered southwest Arizona, near Yuma. More than 5.00 inches (127mm) of precipitation fell in northwest Arizona, with many parts of the state collecting more than an inch of rain. This same system produced more than twice the average annual rainfall in Imperial Valley, California. On the 11th, the remnants of a separate system also passed over southwest Arizona.
August 1951: No tropical cyclones are known to have affected Arizona in the 1940s. However, in the 1950s, the remnants of two more storms affected the state. On August 24, 1951, the moisture from a hurricane that made landfall in Baja California moved over the state, producing more than 5.00 inches (127mm) of precipitation over southwestern Arizona. Flagstaff saw 4.00 inches (102mm) of rain, with similar totals measured at Prescott (3.95 inches; 100mm) and Phoenix (3.24 inches; 82mm). The storm also washed out several roadways near Gila Bend, isolating the city from motorists. Overall, the storm caused $750,000 (1951 USD) in property damage.
July 1954: Three years later, the remnants of another hurricane moved over Arizona from the south during the month of July. Damage from this storm is unknown.
September 1962: Remnant moisture from Tropical Storm Claudia caused severe flash floods in the vicinity of Tucson, with 5 to 7 inches (130 to 180mm) of precipitation falling over the headwaters of the washes of Santa Rosa, Jackrabbit, and Brawley during a 14- to 15-hour period. Over 7 inches (180mm) of rainfall also fell near the Arizona-Sonora Desert Museum. The ensuing flood of the Santa Cruz River and its tributaries produced a path of destruction about 100 miles (160km) long and up to 8 miles (13km) wide. Santa Rosa Wash conveyed 53,100 cubic feet per second (1,500m3/s) at its peak; Los Robles Wash carried up to 32,600cuft/s (920m3/s), while the Santa Cruz River proper peaked at 9,200cuft/s (260m3/s). The washes and rivers reached depths of up to 20 feet (6.1m), and overflowed its banks in places by 1 to 6 feet (0.30 to 1.83m). Flooding from the storm inundated the towns of Marana and Sells, both in Pima County. Total damage in Pima and Pinal Counties exceeded $11 million (1962 USD).
September 1964: The next storm to affect the state was Tropical Storm Tillie in 1964. Although the storm remained at sea, its residual moisture was advected over southern Arizona, allowing a passing cold front to trigger widespread showers and thunderstorms on the evening of September 9. Tucson received 3.05 inches (77mm) of rainfall in a 24-hour period between September 9–10, and two locations—one in the Catalina Mountain foothills and one near Sahuarita—recorded 6.75 inches (171mm) of precipitation. Coupled with rain during the previous week, the Santa Cruz River produced heavy runoff, with peak flows of 15,900cuft/s (450m3/s) recorded near Cortaro.
September 1965: The following year, the remnants of Hurricane Emily crossed into Arizona from Baja California. Any damage from the storm is not known.
September 1966: The remnants of Kirsten caused 1.26 inches (32mm) of rainfall in Nogales.
August 1967: Hurricane Katrina brought heavy rainfall into the southern portion of the state as a tropical depression. The decaying storm produced about 2 inches (51mm) of rainfall across southern Arizona. The peak recorded rainfall occurred at Wellton, where 4.78 inches (121mm) were measured between September 1 and 2. Yuma recorded 1.88 inches (48mm) within a 24-hour period; that was the heaviest rainfall recorded in a four-year period, and was more than the normal rainfall that the city receives during the entire fall season.
August 1968: Two storms approached Arizona in 1968. The first was Tropical Storm Hyacinth in August. It reached the southeastern corner of the state as a tropical depression, and produced showers and thunderstorms over the eastern portion of the state.
October 1968: The last storm to impact Arizona during the decade was Hurricane Pauline, which added high amounts of moisture ahead of a cold front in early October. The added instability in the atmosphere allowed the cold front to produce severe thunderstorms, including an F2 tornado that wrecked several homes and caused $250,000 (1968 USD) in damage when it touched down in Glendale.
September 1970: The remnants of Tropical Storm Norma became Arizona's deadliest storm when they contributed to the disaster known as the "Labor Day storm of 1970". As Norma dissipated, moisture from the cyclone was entrapped in a large extratropical low. Much of the southern and central parts of the state saw 2 to 5 inches (51 to 127mm) of rainfall, and mountainous locations saw between 8 to 11.4 inches (200 to 290mm). Much of the region saw extensive flash flooding that killed 23people and caused significant damage.
October 1971: The following year, Hurricane Olivia produced over 2 inches (51mm) of rainfall across Arizona, triggering flash flood warnings throughout the region. Pinal Ranch reported 5.33 inches (135mm) of precipitation, while Mount Lemmon measured 3.81 inches (97mm). Olivia's remnants also caused three major power outages near Yuma and produced flooding that resulted in the closure of a portion of U.S. Route 95. In Navajo and Pinal counties, the rainfall damaged roads, bridges, sewers, and homes, which amounted to about $250,000 in repair work for the state of Arizona.
October 1972: Hurricane Joanne entered Arizona as a tropical storm before dissipating near Flagstaff. Many areas of the state received between 1 to 3 inches (25 to 76mm) of rainfall, with isolated locations receiving over 5 inches (130mm). The Nogales Highway Bridge over the Santa Cruz River was washed away by the flooding. The heavy rain from Joanne saturated the soils for a later storm that produced flooding that caused $10million (1972 USD) in property damage and eight deaths.
September 1976: On September 11, Hurricane Kathleen entered southern California, producing tropical-storm-force winds over western and possibly southern Arizona. Yuma reported maximum sustained winds of 57 miles per hour (92km/h) and gusts of 76 miles per hour (122km/h) before the measuring station lost power. The winds from Kathleen killed a man when a gust of wind blew a palm tree down onto his mobile home. Severe flooding and hailstorms also resulted. While most of the rainfall from the storm fell in California,2.87 inches (73mm) fell at the Davis Dam on the Colorado River.
October 1976: The next month, Hurricane Liza brought light rain to the state, with the state maximum being 1.48 inches (38mm) on Willow Beach.
October 1977: The remnants of Hurricane Heather caused 8.30 inches (211mm) of rain in Nogales. Extensive bank erosion occurred across southeastern Arizona, as rivers crested over their 100-year flood levels, and 400 people were forced to evacuate their homes. Total damage from the storm was assessed at $15 million (1977 USD).
The 1980s saw destructive tropical cyclones pass through the state, as was the case with the previous decade.
October 1983: A weather system, including moisture from Tropical Storm Octave, caused torrential rains over a ten-day period. The largest precipitation total occurred in Mount Graham, which saw 12.00 inches (305mm) of rain overall. The downpour caused record floods in the San Francisco, Gila, San Pedro, and Santa Cruz rivers. The latter breached its banks near Red Rock, and by its intersection with Interstate 8, had flooded an area over 8 miles (13km) wide. Fourteen people drowned, 975 were injured, and roughly 10,000people were left homeless after the flooding ended. The amount of damage from the disaster was put at $370million (year unknown) USD. Other cities in the state also saw heavy rain, with 9.83 inches (250mm) of precipitation measured at Nogales, 6.67 inches (169mm) at Safford, 6.40 inches (163mm) at Tucson, 3.93 inches (100mm) at Flagstaff, 2.65 inches (67mm) at Phoenix, and 2.62 inches (67mm) at Prescott.
September 1984: Hurricane Norbert entered Arizona as a weakening tropical depression. Sustained winds of 20 to 30 miles per hour (30 to 50km/h) were recorded in the Tucson area. Modest rainfall occurred throughout south-central to northeast Arizona, with most locations reporting between 1 to 2 inches (25 to 51mm) of rain. However, Kitt Peak reported a 30-hour storm rainfall total of 4.15 inches (105mm).
October 1984: The following month, the remnants of Hurricane Polo caused about 1 inch (25mm) of rain over southern and eastern Arizona, with Nogales reporting 1.93 inches (49mm) of precipitation.
October 1989: Flash flooding produced by Hurricane Raymond caused $1.5million (1989USD) in damage in the state. Raymond passed over Arizona as a tropical depression, and produced heavy rainfall on the southeastern portion of the state, with 4.72 inches (120mm) of rain falling in Nogales. About three-quarters of the streets in Willcox were flooded in up to 2 feet (0.61m) of water, and sustained winds of 25 to 35mph (40 to 56km/h) were reported throughout the southeastern corner of the state.
During the 1990s, several tropical systems affected Arizona even after losing all tropical characteristics. However, two hurricanes survived long enough to reach Arizona while still considered tropical systems.
August 1990: The remnants of Hurricane Diana entered Arizona and quickly dissipated, though no rainfall was report throughout the state.
August 1992: Hurricane Lester, reached the state as a tropical storm, and caused over 5 inches (130mm) of precipitation near Phoenix and Tucson. The center of circulation of Lester passed near Tucson on August 24, producing sustained winds of 31mph (50km/h) at Tucson International Airport; the airport also reported gusts of up to 45mph (72km/h), and a drop in central barometric pressure to 999mbar (29.52inHg). Much of the rest of the state reported over 1 inch (25mm) of rain as a result of Lester,. with a peak precipitation measurement of 5.5 inches (140mm) at Cascabel.
August 1995: Flossie's remnants dumped over 3 inches (76mm) of rain over Tucson; one woman died as she tried to cross a flooded stream, and 11 other motorists were stranded in the city. Damage from the storm in Arizona totaled to $5million (1995USD; $8.22million2019USD).
September 1995: That same year, Ismael produced most of its damage south of the state, but light rainfall fell over Cochise County, with the highest reported rainfall being 1.44 inches (37mm).
September 1997: Hurricane Nora, the second storm to reach the state while still retaining tropical characteristics, struck the state in late September and was responsible for the 24-hour rainfall record in the state. Nora produced 11.97 inches (304mm) of rainfall over the Harquahala Mountains in Western Arizona, causing some flash flooding in the area. Near Phoenix, rainfall from the storm caused the Narrows Dam, a small earthen dam, to fail; localized rainfall amounts of up to 3 inches (76mm) occurred throughout the state. Nora also caused 12,000people to lose electric power in Yuma. Nora is believed to be the strongest tropical storm to strike Arizona, as it produced sustained winds of 50 to 60mph (80 to 97km/h) over Yuma. Nora caused $150–200million (1997 USD) in agricultural losses in Arizona.
September 1998: The following month, Hurricane Isis's remnants dropped more than 2 inches (51mm) of rainfall across southern Arizona, resulting in some flash flood warnings and flooding on roadways. Isis also caused up to 3 inches (76mm) across the Santa Catalina and Rincon Mountains that surround Tucson. However, there was no flooding reported in the area, and Tucson International Airport reported only 1.1 inches (28mm) as a result of the storm.
The last decade saw no storms reach Arizona while retaining tropical characteristics; however, numerous remnant lows caused heavy rainfall and flooding throughout the state.
October 2000: The remnants of the first system, Tropical Storm Olivia, produced heavy flash floods in spite of Olivia losing tropical characteristics while located 600miles (965km) west-southwest of Cabo San Lucas, Baja California Sur. However, after being captured by an extratropical cyclone, the remnant low produced widespread heavy rains, with 1.5 to 4 inches (38 to 102mm) of rain falling over most of southeastern Arizona; Hereford saw 8.64 inches (219mm) of rain.
October 2001: Hurricane Juliette dissipated in the Gulf of California, and brought only trace amounts of rainfall to the southern half of the state; the largest amount recorded occurred near Patagonia, where 0.90 inches (23mm) fell.
August 2003: Two years later, the remnants of Hurricane Ignacio produced rainfall over southern Arizona. About 40 residences in Catalina were evacuated due to the risk of flash flooding after 2 inches (51mm) of rainfall fell over the Aspen Fire burn area.
September 2003: That same year, Hurricane Marty brought locally heavy rains to extreme southwestern Arizona in September; in spite of this, there were no reports of flooding from the storm. The highest rain total was 2.83 inches (72mm) at Organ Pipe Cactus National Monument.
September 2004: Javier produced heavy rain throughout the state, helping to alleviate a prolonged drought in the Southwestern United States. The heaviest rainfall occurred at Walnut Creek, which saw a total of 7.00 inches (178mm) of precipitation during the storm. The Tucson airport saw rainfall of 0.37 inches (9.4mm), while the University of Arizona reported 0.89 inches (23mm) of rain. The rain from Javier flooded several roads in the city and, combined with frequent lightning, forced the university to delay one of its football games.
July 2006: The remnants of Tropical Storm Emilia produced an influx of tropical moisture over Arizona, triggering a week-long period of disturbed weather in late July. On July 25, a slow-moving severe thunderstorm dropped several inches of rainfall in a few hours, causing the closure of Interstate 19 when a wash flooded the roadway with running water 8 inches (200mm) deep. The same storm also produced hail with a diameter of 1.75 inches (44mm) north of Rio Rico, and 1 inch (25mm) in Patagonia, and the size of a nickel in the Tohono O'odham Indian Reservation. The next day, another thunderstorm near Elfrida also produced 1-inch (25mm) hail. After one week of widespread rainfall over southeastern Arizona, extensive flooding began to occur. Mount Lemmon saw a 7-day rainfall total of 11.10 inches (282mm); Rillito Creek near the Catalina Mountains conveyed a record flow of 30,000cuft/s (850m3/s). Other streams in the area also saw record flooding, and the Santa Cruz River exceeded flood stage in Marana. The floods caused $4million (2006 USD) in damage.
September 2006: Hurricane John produced about 1 inch (25mm) of rain over Cochise County.
September 2009: The remnants of Hurricane Jimena moved over Arizona on September 5. Near Walapai, water, rock, and other debris covered many roads. In addition, several power lines were down at the Bullhead City Airport. Golf ball-sized hail (1.75 inches (44mm) in diameter) fell northwest of Golden Valley; a weather spotter's house received $5,000 in damage, with all of its windows broken and with damage to his weather station and radio equipment. In Riviera, southwest of Bullhead City, seven mobile home trails were blown with many other receiving some damage due to 80mph (130km/h) wind gusts. In the same area, four people were hurt and total damage was $500,000. North of Mohave Valley, mudslides caused two homes to be destroyed, with 9 others receiving moderate damage, and 16 other receiving minimal damage. Total damage was estimated to be at $600,000. In Laveen, 0.9 inches (23mm) of precipitation fell in a 90-minute period. Heavy rain was recorded in Sedona, thus blocking traffic on State Route 179. in Prescott, street flooding was reported, closing State Route 69 and the Emerald Trail. In Quartzsite, washes overflowed their banks, causing street flooding, and $30,000 in damage. In Tanca, 1 inch (25mm) of precipitation fell within a 30-minute period, thus causing minor flooding with one road being washed out. Damage from that flood totaled $30,000. Yuma also reported 1.62 inches (41mm) of rain from the cyclone. On the afternoon of September 5, a haystack caught fire due to lighting, and was eventually responsible for an additional $20,000 in damage.
September 3, 2013: Moisture from the remnants of Tropical Storm Juliette fueled the monsoon across the southwestern United States, producing scattered showers and thunderstorms.
September 8, 2014: The remnants of Hurricane Norbert produced record-breaking rainfall throughout the central portion of the state. Chandler received 6.09in (155mm) of precipitation, while Phoenix Sky Harbor Airport recorded 3.30in (84mm) of rainfall over a seven-hour period, breaking the 75‑year‑old daily rainfall record. It was also the highest precipitation at Sky Harbor in a single calendar day, but fell short of the station's 24‑hour rainfall total. Accumulations in Chandler and Mesa were deemed to be a 1-in-1,000year event while Phoenix was calculated to be a 1-in-200year event. Two women died, one in Pinal County and one in Tucson; both were swept away by floodwaters in their vehicles. Waters in Tucson reached as deep as 15ft (4.6m). Total damage in Maricopa and La Paz Counties amounted to $17.4million.
September 18, 2014: The remnants of Hurricane Odile brought heavy rainfall to southeastern Arizona.
June 5, 2015: The remnants of Hurricane Andres brought thunderstorms to Arizona, with Phoenix having measurable precipitation on that day for the first time since records began in 1896.
June 9, 2015: Just four days after Andres brought record-breaking rain to the Desert Southwest, another low-pressure system containing the remnants of Hurricane Blanca brought more record-breaking rainfall to many Arizona cities, including Tucson and Yuma.
July 18, 2015: Some of Hurricane Dolores's moisture and remnants were directed into Arizona, bringing showers and thunderstorms. Up to 1 inch of rain was recorded in some places. The heavy rain triggered some flash floods and mudslides near Phoenix.
October 1–2 2018: Hurricane Rosa which at that time was a tropical storm approaching Baja California, left massive rainfall within these two days. More than 2 inches of rain was recorded in some places. Many places were covered with water, some flash floods. 
Tropical Storm Allison was a tropical cyclone that produced severe flooding in the southern United States. The second tropical cyclone and the first named storm of the 1989 Atlantic hurricane season, Allison formed on June 24 in the northwestern Gulf of Mexico. Development of Allison was a result of the interaction of a tropical wave and the remnants of Pacific hurricane Hurricane Cosme. It moved south and became a tropical storm on June 26. By June 27, Allison made landfall near Freeport, Texas. Allison quickly weakened to a tropical depression later that day, and transitioned into an extratropical cyclone on the following day.
Hurricane Javier was the tenth named storm and the sixth and final hurricane of the 2004 Pacific hurricane season. Javier was also the strongest hurricane of the 2004 season, with 150 mph (240 km/h) winds and a central pressure of 930 millibars. However, because of high wind shear in the East Pacific, Javier weakened rapidly before making landfall in Baja California as a tropical depression. The remnants of the storm then continued moving northeast through the Southwestern United States. Javier caused no direct fatalities, and the damage in Mexico and the United States was minimal.
Tropical Storm Alberto was the first tropical storm of the 2006 Atlantic hurricane season. Forming on June 10 in the northwestern Caribbean, the storm moved generally to the north, reaching a maximum intensity of 70 mph (110 km/h) before weakening and moving ashore in the Big Bend area of Florida on June 13. Alberto then moved through eastern Georgia, North Carolina, and Virginia as a tropical depression before becoming extratropical on June 14.
Tropical Storm Grace was a weak tropical storm that struck Texas in the 2003 Atlantic hurricane season. The eleventh tropical depression and the seventh tropical storm of the season, Grace was also the weakest storm of the season. On August 30 the storm developed from a long-track tropical wave in the western Gulf of Mexico. Grace remained disorganized throughout its lifetime due to an upper level low to its west. The weak storm moved northwestward and made landfall on southeastern Texas. Grace quickly weakened over land, and dissipated on September 2 as it merged into a cold front.
Tropical Storm Marco was the only tropical cyclone to make landfall on the United States during the 1990 Atlantic hurricane season. The 13th named storm of the season, Marco formed from a cold-core low pressure area along the northern coast of Cuba on October 9, and tracked northwestward through the eastern Gulf of Mexico. With most of its circulation over the western portion of Florida, Tropical Storm Marco produced 65 mph (100 km/h) winds over land. However, it weakened to a tropical depression before moving ashore near Cedar Key. The cyclone combined with a cold front and the remnants of Hurricane Klaus to produce heavy rainfall in Georgia and the Carolinas. After interacting with the nearby Hurricane Lili, Marco continued northward until being absorbed by a cold front on October 13.
Hurricane Isis was the only hurricane to make landfall during the 1998 Pacific hurricane season. The ninth tropical storm and sixth hurricane of the season, Isis developed on September 1 from an interaction between a tropical wave and a large surface circulation to the southwest of Mexico. It moved northward, striking the extreme southeastern portion of the Baja California peninsula before attaining hurricane status in the Gulf of California. Isis made landfall at Topolobampo in the Mexican state of Sinaloa on September 3, and quickly lost its low-level circulation. The remnants persisted for several days before dissipating in the U.S. state of Idaho.
Hurricane Lester was the first Pacific tropical cyclone to enter the United States as a tropical storm since 1967. The twelfth named storm and seventh hurricane of the 1992 Pacific hurricane season, Lester formed on August 20 from a tropical wave southwest of Mexico. The tropical storm moved generally northwestward while steadily intensifying. After turning to the north, approaching the Mexican coast, Lester attained hurricane status. The hurricane reached peak winds of 85 mph (140 km/h) before making landfall on west-central Baja California. The system weakened while moving across the peninsula and then over northwestern Mexico. Not long after entering Arizona, Lester weakened to a tropical depression, and dissipated on August 24, 1992, over New Mexico.
Tropical Storm Octave was considered the worst tropical cyclone in the history of Arizona. The origins of Tropical Storm Octave were from a tropical disturbance that formed south of the Gulf of Tehuantepec on September 23, 1983. Steered by a deep layer high over Mexico, the disturbance moved west for four days before becoming a tropical depression on September 27 off the southwest coast of Mexico. Over an area of warm sea surface temperatures, it was able to quickly strengthen to peak winds of 50 mph (85 km/h), through wind shear prevented much further development. By September 30, Octave was accelerating to the northeast, steadily weakening due to cooler waters. That day it weakened to tropical depression status, and on October 2, Octave dissipated.