 Destruction of the Spirit Lake Outlet Bridge | |
| Date | May 14, 2023 |
|---|---|
| Location | Mount St. Helens National Volcanic Monument |
| Cause | Soil saturation due to heavy rainfall and snowmelt |
| Deaths | 0 |
| Non-fatal injuries | 0 |
| Missing | 12 (temporarily stranded) |
The 2023 South Coldwater Slide is a mudslide that occurred in May 2023 near Mt. St. Helens. The volume of debris, and subsequent destruction of a bridge, closed off Washington State Route 504 and access to the Mount St. Helens National Volcanic Monument.
On May 14, 2023, a mudslide and debris flow, given the moniker "South Coldwater Slide" by the U.S. Forest Service (USFS), [1] destroyed the 85-foot (26 m) Spirit Lake Outlet Bridge and severed SR 504 northeast of Johnston Ridge Observatory at milepost 49. Twelve people were airlifted from the area beyond the mudslide; the observatory's seasonal reopening was postponed and the highway east of Coldwater Lake was closed to all traffic. [2] [3] Three days later, the closure was temporarily expanded further west to milepost 43 due to potential hazards revealed by geotechnical engineers during their investigation; access to Coldwater Lake and local trails was restored in June after the closure was moved back to milepost 49 at the site of the slide. [4] [5]
A team composed of USFS staff and volunteers hiked to the observatory to retrieve scientific equipment and supplies so that observation of the volcano could proceed at the Coldwater Science and Learning Center. [6] The center was outfitted with exhibits and other facilities as a temporary alternative to the Johnston Ridge Observatory, providing the continuation of services for visitors to the area while cleanup and repairs were underway. [7] Washington State Department of Transportation (WSDOT) contractors cleared debris over the highway by July and created a temporary gravel road to access Johnston Ridge for vehicle retrieval and to prepare for reopening in 2024. [8] [9] Power was restored to the observatory and monitoring equipment of the volcano was declared as back to "full functionality". [10] Marie Gluesenkamp Perez, the U.S. Representative of the district, toured the slide in August and co-sponsored the renewal of the National Landslide Preparedness Act the following year. [11]
The interim roadway was washed out in November 2023 after the replacement culverts failed due to heavy rainfall and erosion which was unrelated to the prior South Coldwater Slide event. There were no changes to the admittance of previously reopened recreation areas but the timeline to fully reopen SR 504 to the observatory in 2024 was called into doubt by the USFS. [12] Further investigation of the site by WSDOT engineers revealed difficulties in making additional repairs to the bypass. A temporary fix was considered to be uneconomical and it would further delay a permanent rebuild. Delays in temporarily or permanently reopening the bridge and highway for regular use is also due to a combination of the limited construction schedule based on weather, high elevation, and the steep slope of the area. [13]
The USFS announced that the highway and access to the observatory was to remain closed until late 2026. [14] After the loss of the bypass, the closure of SR 504 was listed between milepost 45.2 and 51, and the observatory is without power. [15] With construction not slated until April 2026, WSDOT revised the planned reopening of both the road and observatory to April 2027. [16]
The slide, measured at 300,000 cubic yards (230,000 m3), [10] was determined not to be associated with seismic or volcanic activity, but caused by the cumulative effects of melting snow and the oversaturation of the volcanic soil in the area. [17]
Mount St. Helens is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It lies 52 miles (83 km) northeast of Portland, Oregon, and 98 miles (158 km) south of Seattle. Mount St. Helens takes its English name from that of the British diplomat Alleyne Fitzherbert, 1st Baron St Helens, a friend of explorer George Vancouver who surveyed the area in the late 18th century. The volcano is part of the Cascade Volcanic Arc, a segment of the Pacific Ring of Fire.
On March 27, 1980, a series of volcanic explosions and pyroclastic flows began at Mount St. Helens in Skamania County, Washington, United States. A series of phreatic blasts occurred from the summit and escalated until a major explosive eruption took place on May 18, 1980, at 8:32 am. The eruption, which had a volcanic explosivity index of 5, was the first to occur in the contiguous United States since the much smaller 1915 eruption of Lassen Peak in California. It has often been declared the most disastrous volcanic eruption in U.S. history.
Spirit Lake is a lake in Skamania County, Washington, United States, located north of Mount St. Helens. It was a popular tourist destination for many years until Mount St. Helens erupted in 1980. Previously there had been six camps on the shore of Spirit Lake: Boy Scout, the Girl Scout Camp at Spirit Lake, two YMCA camps, Harmony Fall Lodge, and another for the general public. There were also several lodges accessible to visitors, including Spirit Lake Lodge and Mt. St. Helens Lodge. The latter was owned and operated by Harry R. Truman, a noted victim of the volcano's 1980 eruption.
Mount St. Helens National Volcanic Monument is a U.S. National Monument that includes the area around Mount St. Helens in Cowlitz and Skamania Counties, Washington. It was established on August 27, 1982, by U.S. President Ronald Reagan, following the 1980 eruption. The 110,000 acre (445 km2) National Volcanic Monument was set aside for research, recreation, and education. Inside the monument, the environment is left to respond naturally to the disturbance. It was the third national monument to be managed by the U.S. Forest Service and is part of the Gifford Pinchot National Forest.
David Alexander Johnston was an American United States Geological Survey (USGS) volcanologist who was killed by the 1980 eruption of Mount St. Helens in the U.S. state of Washington. A principal scientist on the USGS monitoring team, Johnston was killed in the eruption while manning an observation post six miles (10 km) away on the morning of May 18, 1980. He was the first to report the eruption, transmitting "Vancouver! Vancouver! This is it!" before he was swept away by a lateral blast; despite a thorough search, Johnston's body was never found, but state highway workers discovered remnants of his USGS trailer in 1993.
Harry Glicken was an American volcanologist. He researched Mount St. Helens in the United States before and after its 1980 eruption, and was very distraught about the death of volcanologist David A. Johnston, who was Glicken's mentor and supervisor in Spring 1980 at Mount St. Helens. Glicken was initially assigned to the USGS observation post in the weeks leading up to the eruption but was called away the night before the eruption.
State Route 504 is a state highway in southwestern Washington state in the United States. It travels 52 miles (84 km) along the North Fork Toutle River to the Mount St. Helens area, serving as the main access to the Mount St. Helens National Volcanic Monument. The highway begins at an interchange with Interstate 5 (I-5) and SR 411 in Castle Rock and terminates at the Johnston Ridge Observatory near Spirit Lake.
The Washington State Department of Transportation is a governmental agency that constructs, maintains, and regulates the use of transportation infrastructure in the U.S. state of Washington. Established in 1905, it is led by a secretary and overseen by the governor. WSDOT is responsible for more than 20,000 lane-miles of roadway, nearly 3,000 vehicular bridges and 524 other structures. This infrastructure includes rail lines, state highways, state ferries and state airports.
State Route 113 (SR 113), also known as Burnt Mountain Road, is a Washington state highway in Clallam County on the Olympic Peninsula. It connects U.S. Route 101 (US 101) at Sappho to SR 112 near Clallam Bay, traveling north along Beaver Creek and the Pysht River for 10 miles (16 km).
State Route 6 (SR 6) is a 51.37-mile (82.67 km) long state highway in Pacific and Lewis counties in the U.S. state of Washington. The highway, which extends from U.S. Route 101 (US 101) in Raymond east to Interstate 5 (I-5), co-signed with US 12, in Chehalis. Major communities located on the highway include Raymond, Pe Ell, Adna and Chehalis. The first state highway that used the current route of SR 6 was State Road 19, established in 1913. State Road 19 became State Road 12 in 1923, which became Primary State Highway 12 (PSH 12) in 1937. In 1964, PSH 12 became SR 6 and since, three minor construction projects have been arranged, only two have been completed.
Silver Lake, sometimes Silverlake, is an unincorporated community in Cowlitz County, Washington, in the southwestern portion of the state. Silver Lake is located 6 miles (9.7 km) east of Castle Rock along Washington State Route 504, which is also known as the Spirit Lake Memorial Highway. The area considered Silverlake is about 6 miles (10 km) east of Interstate 5 (I-5) and is approximately 50 miles (80 km) from Portland, Oregon, to the south and Seattle about 110 miles (180 km) to the north. The closest cities to the subject property are Castle Rock, six miles (10 km) to the west, and Toutle, four miles (6 km) east.
St. Helens is a 1981 made-for-cable HBO television film directed by Ernest Pintoff, and starring David Huffman, Art Carney, Cassie Yates, and Albert Salmi. The film centers on the events leading up to the cataclysmic 1980 eruption of Mount St. Helens in Washington, with the story beginning on the day volcanic activity started on March 20, 1980, and ending on the day of the eruption, May 18, 1980. The film premiered on May 18, 1981, on the first anniversary of the eruption.
State Route 530 (SR 530) is a state highway in western Washington, United States. It serves Snohomish and Skagit counties, traveling 50.52 miles (81.30 km) from an interchange with Interstate 5 (I-5) southwest of Arlington past SR 9 in Arlington and Darrington to end at SR 20 in Rockport. Serving the communities of Arlington, Arlington Heights, Oso, Darrington and Rockport, the roadway travels parallel to a fork of the Stillaguamish River from Arlington to Darrington, the Sauk River from Darrington to Rockport and the Whitehorse Trail from Arlington to Darrington.
State Route 263 is a 9.24-mile (14.87 km) long state highway in the U.S. state of Washington, serving rural Franklin County and the Lower Monumental Dam. The highway begins at the Port of Windust on the Snake River and travels east to the Lower Monumental Dam and north to SR 260 in Kahlotus, paralleling the Columbia Plateau Trail. Devils Canyon carried traffic on the Spokane, Portland and Seattle Railway in the early 20th century before the completion of a road serving the Lower Monumental Dam in 1961. The Devils Canyon Road was paved and signed as SR 263 in 1991 and the railroad became the Columbia Plateau Trail the same year.
Toutle is an unincorporated community in Cowlitz County, Washington.
A major landslide occurred 4 miles (6.4 km) east of Oso, Washington, United States, on March 22, 2014, at 10:37 a.m. local time. A portion of an unstable hill collapsed, sending mud and debris to the south across the North Fork of the Stillaguamish River, engulfing a rural neighborhood, and covering an area of approximately 1 square mile (2.6 km2). Forty-three people were killed and 49 homes and other structures destroyed. The landslide has been described as one of, if not the most, deadly landslide in American history.
Kid Valley is an unincorporated community in Cowlitz County, Washington. Kid Valley is located east of the city of Castle Rock and along the North Fork Toutle River. Kid Valley is reached by traveling 17.8 miles (28.6 km) east of Castle Rock along Washington State Route 504, which is also known as the Spirit Lake Memorial Highway. The Kid Valley community is part of the Toutle Lake School District, a K-12 school district of about 600 students.
Coldwater Lake is a barrier lake on the border of Cowlitz County and Skamania County, Washington in the United States. The lake was created during the 1980 eruption of Mount St. Helens, which blocked its natural outlet, Coldwater Creek, with volcanic debris. It is one of several lakes in the area that were created or otherwise enlarged by the eruption.
Windy Ridge is a ridge and eponymous Forest Highway in the Mount St. Helens National Volcanic Monument. The ridge goes between Windy Pass and Independence Pass, 1 mile (1.6 km) east of Spirit Lake. Several road guides list Windy Ridge Road (NF-99) as one of the best roads in Washington State due to its good pavement, good views, and winding "sweeper" curves enjoyable to many drivers and motorcycle riders. At the end of the road at 4,200 feet (1,300 m) elevation, at 46°15′00″N122°08′14″W above Spirit Lake, there is a viewpoint into the St. Helens crater.
Coldwater Peak is a 5,722 ft (1,740 m) mountain summit located in Mount St. Helens National Volcanic Monument, in the Gifford Pinchot National Forest, in Skamania County of southwest Washington state. It is situated in the Cascade Range, 2 mi (3.2 km) northwest of Spirit Lake, and 2 mi (3.2 km) east of Coldwater Lake. Its nearest higher neighbor is Mount Margaret, 2.4 mi (3.9 km) to the northeast, and Mount St. Helens rises 7 mi (11 km) to the south. Precipitation runoff from Coldwater Peak drains into Coldwater Creek, a tributary of the North Fork Toutle River. The mountain takes its name from this creek, and was officially adopted in 1983 by the U.S. Board on Geographic Names. A trail provides access to the summit, the site of the former Coldwater Lookout from 1935 to 1968, and now is a site for research instruments.