Washington State Route 504

State Route 504 (SR 504, also known as the Spirit Lake Memorial Highway^[1]) is a state highway in Cowlitz and Skamania counties, in the U.S. state of Washington. It extends 51.76 miles (83.30 km) from an interchange with Interstate 5 (I-5), SR 411 and Interstate 5 Business (I-5 Bus) in the city of Castle Rock, east to end at the Johnston Ridge Observatory. The route serves as a connector from Castle Rock to Mount St. Helens NVM.

The highway formerly was Secondary State Highway 1R (SSH 1R) from 1937 until 1964. SSH 1R ran from Castle Rock to the border of the Columbia National Forest (now known as the Gifford Pinchot National Forest) from 1937 until 1961. In 1961, the Washington State Legislature extended SSH 1R east to Spirit Lake. In 1964, SSH 1R became SR 504. When Mount St. Helens erupted on May 18, 1980, SR 504 was closed and was heavily damaged from SR 505 to Spirit Lake. The highway was rebuilt and partially opened in 1991 on a higher and safer route to Coldwater Ridge. The new highway was completed when the road to the Johnston Ridge Observatory was opened in 1994.

SR 504 also has a spur route, named SR 504 Spur, that runs along the former route of SR 504 in the Gifford Pinchot National Forest. The route extends 0.87 miles (1.40 km) along the former route of SR 504, before the Mount St. Helens eruption. The highway closes every winter because of snow and dangerous cliffs.

Route description

SR 504 runs 51.76 miles (83.30 km) from an interchange with Interstate 5 (I-5), SR 411 and Interstate 5 Business (I-5 Bus) in the city of Castle Rock, east to end at the Johnston Ridge Observatory.^[3][4] The route serves as a connector from Castle Rock to Mount St. Helens NVM.^[3] WSDOT has found that more than 14,000 motorists utilize the road daily after the interchange with I-5 based on average annual daily traffic (AADT) data.^[5]

Castle Rock to Kid Valley

SR 504 starts at an interchange with I-5, SR 411 and I-5 Bus north of Downtown Castle Rock.^[6] 0.15 miles (0.24 km) after the interchange, the highway intersects the Old Pacific Highway,^[2] which formerly was U.S. Route 99.^[7] The road turns north after the intersection and leaves Castle Rock 0.51 miles (0.82 km) north of the interchange.^[2] After turning back east, the road goes south again to turn east towards Seaquest State Park, a 475 acres (192.23 ha) state park,^[8] located 5.25 miles (8.45 km) east of Castle Rock.^[2] After passing the state park, SR 504 starts to parallel the shoreline of Silver Lake and passes the community of Silverlake.^[9]

The highway stops paralleling the shoreline of Silver Lake after passing the Silver Lake Cemetery on the north side of the road. SR 504 continues northeast to Toutle, where the highway crosses the Toutle River.^[2] After crossing the river and leaving Toutle, the highway intersects SR 505's eastern terminus. The road then crosses the North Fork of the Toutle River and enters Kid Valley, Washington.^[9]

Kid Valley to Johnston Ridge

After leaving Kid Valley, SR 504 intersects SR 504 Spur, which follows the older route of SR 504 before the eruption 0.87 miles (1.40 km) to a viewpoint.^[2] One of the sights that can be seen is the buried A frame; a house that was partially buried by the lahar flow in 1980. Also nearby is the location where Megan Masser sighted Bigfoot in June 1991.

After the sasquach crossing zone and buried A-Frame the sediment dam is to the right. A giant mud lake exists behind the dam to allow sediment to collect and settle to prevent the ash flowing down the river from clogging up the Columbia River shipping lanes. After crossing the North Fork of the Toutle River once more, the highway crosses Hoffstadt Creek on the Hoffstadt Creek Bridge, a 2,340 feet (713.23 m) long and 370 feet (112.78 m) high bridge built after the eruption,^[10] one of 14 new bridges.^[10] About 3.37 miles (5.42 km) after the bridge, the road passes the Forest Learning Center and follows the northern boundary of the Mount St. Helens NVM before actually entering it.^[11]

After entering the National Monument, SR 504 splits and has a partial cloverleaf interchange with itself.^[12] The westbound lanes are known as State Route 504 Loop.^[2] After the interchange, the highway curves twice down a cliff and starts to run along the shoreline of Coldwater Lake. After looping back northeast, the road leaves Cowlitz County and enters Skamania County. SR 504 then goes east to its easternmost point and curves back west to the Johnston Ridge Observatory.^[11][13]

Former route

About 21.03 miles (33.84 km) east of Castle Rock, the new alignment of SR 504 starts.^[2][14] The old route is now known for the first 0.87 miles (1.40 km) of the route as SR 504 Spur.^[2] SR 504 Spur goes from SR 504 to a viewpoint.^[2][15] Then, the old route goes east along the North Fork of the Toutle River passing the abandoned community of St. Helens before crossing the river.^[14] The highway then went east along the shoreline of Spirit Lake to the community of Spirit Lake and then south to Mount St. Helens.^[14]

History

1937 – 1980

When the Primary and Secondary Highways were created in 1937, the former route of SR 504 became Secondary State Highway 1R (SSH 1R).^[16] SSH 1R ran from Primary State Highway 1 (PSH 1) and SSH 12H in Castle Rock east past SSH 1Q to the border of the Columbia National Forest,^[17] now known as Gifford Pinchot National Forest,^[17] in 1937.^[16]

In 1961, the Washington State Legislature extended SSH 1R east to Spirit Lake.^[18] SSH 1R became SR 504 in 1964 during the 1964 highway renumbering, in which the Washington State Department of Transportation (WSDOT) replaced the previous system of Primary and Secondary Highways with a new system called State Routes, which is still in use today.^[19][20] From 1964 until 1980, SR 504 ran along the shores of the North Fork of the Toutle River,^[14] but was rerouted to partially follow Bear Creek.^[14]

1980 – 2001

On May 18, 1980, Mount St. Helens erupted after two months of small earthquakes and pre-avalanche eruptions.^[21] SR 504 was heavily damaged after the eruption from floodwaters and was closed for reconstruction.^[21] In 1982, the Washington State Legislature named SR 504 the Spirit Lake Memorial Highway in honor of Spirit Lake and the 57 people killed by the eruption.^[1][22]

After the highway was reconstructed on a route farther from the river, it partially opened from SR 505 to Coldwater Ridge in 1991. Later, in 1994, it officially opened from Coldwater Ridge to the Johnston Ridge Observatory; Coldwater Ridge was later named Johnston Ridge to honor volcanologist David A. Johnston,^[23] who perished there observing the eruption.^[24][25] Also in 1994, five new tourist centers were being planned because of a boost in tourism.^[26] The United States Forest Service planned three, Cowlitz County and Weyerhaeuser each planned one.^[26]

2001 – present

In 2001, a proposal for a highway connecting SR 504 to National Forest Route 99 on the eastern part of the mountain was started.^[27] The highway was proposed to be 7 miles (11 km) long going through an area known as Pumice Plain and would cost $20 million USD.^[27] WSDOT repaved SR 504 from Castle Rock to the Toutle River Bridge in 2003.^[28]

From 2004 until 2006, Mount St. Helens started having magma seep onto the surface and small ash plumes rise.^[29][30] In March 2007, WSDOT completely closed SR 504 from Kid Valley to Johnston Ridge because of an unstable slope about 19.9 miles (32.0 km) east of Castle Rock.^[31][32] The highway later opened to traffic on April 2, 2007.^[33] WSDOT closes SR 504 during the winter every year and reopens by spring.^[34]

Sometimes certain portions of the road are closed and reopened, such as Cow Creek,^[35] Bear Creek,^[36] and the Coldwater Visitor Center.^[37] During 2008, with snow going into April, SR 504 wasn't opened until May 16.^[38][39]

Major intersections

State Route 504 Spur

State Route 504 Spur (SR 504 Spur) is the spur route of SR 504 located within Gifford Pinchot National Forest.^[15] The route extends 0.87 miles (1.40 km) along the former route of SR 504, before the Mount St. Helens eruption.^[2] WSDOT has found that more than 90 motorists utilize the road daily based on average annual daily traffic (AADT) data.^[5] The road connects to a viewpoint and the spur's full name from WSDOT is State Route 504 Spur Old504.^[2] The spur is known as Sediment Dam Road for its entire length.^[2]

References

External links

• Highways of Washington State
• West Coast Roads
• Washington State Department of Transportation: SR 504 – Castle Rock to Toutle River Bridge
• Johnston Ridge Observatory