Freezing rain is the name given to rain maintained at temperatures below freezing by the ambient air mass that causes freezing on contact with surfaces. Unlike a mixture of rain and snow, ice pellets, or hail, freezing rain is made entirely of liquid droplets. The raindrops become supercooled while passing through a sub-freezing layer of air hundreds of meters above the ground, and then freeze upon impact with any surface they encounter, including the ground, trees, electrical wires, aircraft, and automobiles. The resulting ice, called glaze ice, can accumulate to a thickness of several centimeters and cover all exposed surfaces. The METAR code for freezing rain is FZRA.
A winter storm warning is a statement made by the National Weather Service of the United States which means a winter storm is occurring or is about to occur in the area, usually within 36 hours. Generally, a Winter Storm Warning is issued if the following criteria, at least, are forecast: usually between 4 inches (10 cm) to 7 inches (18 cm) or more of snow or usually 3 inches (7.6 cm) or more of snow with a large accumulation of ice. In the Southern United States, where severe winter weather is much less common and any snow is a more significant event, warning criteria are lower, as low as 1 inch (2.5 cm) in the southernmost areas: as one goes from north to south, the necessary accumulations lessen. A warning can also be issued during high impact events of lesser amounts, usually early or very late in the season when trees have leaves and damage can result. Winter Storm Warnings are issued when winds are less than 35mph; if the storm has winds above this wind speed, it becomes a blizzard warning.
The Blizzard of 1996 was a severe nor'easter that paralyzed the United States East Coast with up to 4 feet (1.2 m) of wind-driven snow from January 6 to January 8, 1996. This storm was a classic example of a nor'easter, but the storm would not have been as historically significant without the presence of the arctic high pressure system located to the north of New York. It was followed by another storm, an Alberta Clipper, on January 12, then unusually warm weather and torrential rain which caused rapid melting and river flooding. Along with the March Superstorm of 1993, it is one of only two snowstorms to receive the top rating of 5, or "Extreme", on the Northeast Snowfall Impact Scale (NESIS).
The Northeast Snowfall Impact Scale (NESIS) was created to measure snowstorms in the U.S. Northeast in much the same way the Saffir-Simpson Hurricane Scale records hurricane intensity and the Enhanced Fujita Scale with tornadoes.
The Early Winter 2006 North American storm complex was a severe winter storm that occurred on November 26, 2006, and continued into December 1. It affected much of North America in some form, producing all kinds of severe weather including a major ice storm, blizzard conditions, high winds, extreme cold, a serial derecho and some tornadoes.
The December 2009 North American blizzard was a powerful nor'easter that formed over the Gulf of Mexico in December 2009, and became a major snowstorm that affected the East Coast of the United States and Canadian Atlantic provinces. The snowstorm brought record-breaking December snowfall totals to Washington, D.C., Baltimore, and Philadelphia.
The 2009 North American Christmas blizzard was a powerful winter storm and severe weather event that affected the Midwestern United States, Great Plains, Southeastern United States, the Eastern Seaboard, and parts of Ontario. The storm began to develop on December 22 before intensifying to produce extreme winds and precipitation by the morning of December 24. The storm's rapid development made it difficult for forecasters to predict. The blizzard was reported to have claimed at least 21 lives, and disrupted air travel during the Christmas travel season. In the Southeastern and Central United States, there were 27 reported tornadoes on December 23–24. The storm, a Category 5 "Extreme" one on the Regional Snowfall Index, was the first winter weather event to rank as such since the Blizzard of '96.
Global storm activity of 2009 profiles the major worldwide storms, including blizzards, ice storms, and other winter events, from January 1, 2009 to December 31, 2009. Wintery storms are events in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form. It may be marked by strong wind, thunder and lightning, heavy precipitation, such as ice, or wind transporting some substance through the atmosphere. Summer storms including flooding, severe thunderstorms and extratropical cyclones are also included in this list to a certain extent.
Global storm activity of 2008 profiles the major worldwide storms, including blizzards, ice storms, and other winter events, from January 1, 2008 to December 31, 2008. A winter storm is an event in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form. It may be marked by strong wind, thunder and lightning, heavy precipitation, such as ice, or wind transporting some substance through the atmosphere. Major dust storms, Hurricanes, cyclones, tornados, gales, flooding and rainstorms are also caused by such phenomena to a lesser or greater existent.
Global storm activity of 2006 profiles the major worldwide storms, including blizzards, ice storms, and other winter events, from January 1, 2006 to December 31, 2006. Winter storms are events in which the dominant varieties of precipitation are forms that only occur at cold temperatures, such as snow or sleet, or a rainstorm where ground temperatures are cold enough to allow ice to form. It may be marked by strong wind, thunder and lightning, heavy precipitation, such as ice, or wind transporting some substance through the atmosphere. Other major non winter events such as large dust storms, Hurricanes, cyclones, tornados, gales, flooding and rainstorms are also caused by such phenomena to a lesser or greater existent.
The December 1969 nor'easter was a strong winter storm that mainly affected the Northeastern United States and southern Quebec between December 25 and December 28, 1969. The multi-faceted storm system included a tornado outbreak, record snow accumulations, a damaging ice storm, and flooding rains.
The 2013–14 North American winter refers to winter in North America as it occurred across the continent from late 2013 through early 2014. The winter of 2013–14 was one of the most significant for the United States, due in part to the breakdown of the polar vortex in November 2013, which allowed very cold air to travel down into the United States, leading to an extended period of very cold temperatures. The pattern continued mostly uninterrupted throughout the winter and numerous significant winter storms affected the Eastern United States, with the most notable one being a powerful winter storm that dumped ice and snow in the Southeast and Northeast in mid-February. Most of the cold weather abated by the end of March, though a few winter storms did affect the western portions of the U.S. towards the end of the winter.
The 2015–16 North American winter refers to winter in North America as it occurred across the continent from late 2015 through early 2016. Contrary to the past two winters, the United States experienced warmer conditions, mainly due to a strong El Niño. However, despite the warmth, significant weather systems still occurred, including a a snowstorm and flash flooding in Texas at the end of December and a large tornado outbreak at the end of February. The main event of the winter was when a crippling and historic blizzard struck the Northeast in late January, dumping up to 3 feet of snow in and around the metropolitan areas.
The 2011–12 North American winter refers to winter in North America as it occurred across the continent from late 2011 through early 2012. The 2011–12 season by and large saw above normal average temperatures across North America, with the contiguous United States encountering its fourth-warmest winter on record along with an unusually low number of significant winter precipitation events. The primary outlier was Alaska, which experienced its coldest January on record.
The 2010–11 North American winter season started in late 2010 and ended in mid-2011.
The 2016–17 North American winter refers to winter in North America as it occurred across the continent from late 2016 through early 2017. During the winter, a weak La Niña was expected to influence weather conditions across the continent. Several notable events occurred during the season, including a potent winter storm that affected the East Coast of the United States in early January, the second-largest winter tornado outbreak on record later that month, and an unusually warm February. In addition, towards the end of the season, a large cyclonic storm system that caused a large tornado outbreak, flooding, and a potent blizzard in the heart of the country. However, the most notable event of the winter was a powerful blizzard that impacted the Northeast and New England in mid-March, towards the end of the season.
The 2017–18 North American winter refers to winter in North America as it occurred across the continent from late 2017 through early 2018. Similar to the previous winter, a La Niña was expected to influence the winter weather across North America. Winter weather patterns were very active, erratic, and protracted, especially near the end of the season. Significant events included rare snowfall in the South, a strong cold wave that affected the United States during the early weeks of January, and a series of strong nor'easters that affected the Northeastern U.S during the month of March. In addition, flooding also took place during the month of February in the Central United States. Finally the winter came to a conclusion with a powerful storm system that caused a tornado outbreak and flooding in mid-April. The most intense event, however, was an extremely powerful cyclonic blizzard that impacted the northeastern United States in the first week of 2018.
The 2018–19 North American winter was winter in North America as it was occurring across the continent from late 2018 through early 2019. Notable events have included snow in the Southeast in December, a strong cold wave and several major winter storms in the Midwest, Northeast and much of Canada late January and early February, record snowstorms in the Southwest late February, two nor'easters that affected the east coast early March, deadly tornado outbreaks in the Southeast, collapsing buildings in Quebec, a historic mid-April blizzard in the Midwest, but the most notable event all season was a record-breaking bomb cyclone that affected much of North America mid March. Unlike previous winters, a developing El Niño was expected to influence weather patterns across North America.
The January 2019 North American winter storm was a long-lived winter storm, forming as a large area of low pressure off the Pacific Northwest shoreline January 16, making its way to the Northeast by January 21. Its effects included heavy rain/high elevation snow and gusty winds in California, Severe weather in the south, near-blizzard conditions in Upstate New York, an Ice Storm in New England and minor coastal flooding in the Mid-Atlantic.