Spring Road Clearing

A yellow snowplow clears snow backed by a snow-covered mountain
A snow plow clears snow near the Devastated Area.
 

Learn and Explore

The 30-mile Lassen Volcanic National Park Highway traverses avalanche-prone slopes with up to 2,000 foot drops and can hold a snowpack up to 40 feet deep. Snow clearing operations usually begin in March or April and continues for about two months before the highway is entirely open.

Once a section of road is cleared, it remains closed to vehicles until the last layer of snow and ice melts and all road preparations (e.g. signs, shoulder grading) are complete. At that time, the section may open to vehicles. Visitors can enjoy hiking or biking sections of the highway once they are cleared of snow and before they open to vehicles.

 

On This Page Navigation

 
Map of park roads colored red for not cleared, orange for cleared but closed to vehicles, and green for open to vehicles.
Map of road status and snow clearing progress as of 4/9/2021.
 

Road Clearing Operator Log

Log updates are posted when reports are received from road crew members. The latest update may not reflect the current status. The road crew works Monday through Thursday, 10 hours per day.

April 9, 2020 - We ended our week at Emerald Lake, just below Bumpass Hell Trailhead parking area. That gives us a total of 5.5 miles for the first week. Caltrans will be starting to assist with the large parking lots Tuesday.

April 5, 2021 - Crew completed clearing between Kohm Yah-mah-nee Visitor Center and Windy Point (0.5 mile beyond Sulphur Works). Snow depth is lower-than-average at 6 to 8 feet.

March 23, 2021 - Clearing to Devastated Area was completed today. hikers and bicyclists can enjoy the cleared road until it opens to vehicles when conditions permit (see map above for current status). Thank you to CalTrans in assisting with steady snow removal and re-clearing the new snow that fell March 8. Road crew will transport equipment to the Southwest Entrance in preparation to begin clearing operations either around March 31. There is approximately 8 feet of snow on the road in the Southwest Area. The clearing process goes more slowly in this area due to the steep slopes, avalanches, hairpin turns, and heavy snow drifts.

March 19, 2021 - Road crew has cleared the park highway between Loomis Plaza and Hot Rock (6.7 miles). Progress was slower than usual due to equipment issues and new snowfall. Road crew will continue clearing to Devastated Area on Monday, 3/22.

March 3, 2021 - Road crews have completed initial snow clearing operations along the Manzanita Lake Campground Road and in the Manzanita Lake Campground (opens 5/21). CalTrans has cleared the park highway between Loomis Plaza and Sunflower Flat (2.5 miles) and will continue towards Devastated Area (10 miles). Once the highway is cleared to Devastated Area, road crews will begin clearing in the Southwest Area. This could possibly occur as early as the last week of March, depending on weather and equipment.

 
 
Three stacked images showing snow on a highway, a couple on road flanked by snow, and a curving road cut into snow below a peak
Top: Winter road conditions at the Southwest Entrance, people walking on the park highway, a cleared section of highway below Lassen Peak.

When Will the Highway Open to Through Traffic?

Road crews begin clearing snow from the park highway in March or April, depending on snow depth and weather forecasts. It is not possible to predict when the highway will open to through traffic, because weather and other delays can affect the clearing process significantly. A chart below provides opening and closing dates of the park highway since 1980. The park does not clear snow from Butte Lake, Warner Valley, or Juniper Lake Roads. The paved sections of Warner Valley and Juniper Lake Roads are maintained by Plumas County and are usually not plowed.

Snow clearing operations occur in the following order:

  1. Manzanita Lake Area between Loomis Plaza and Devastated Area (10 miles).
  2. Southwest Area between Kohm Yah-mah-nee Visitor Center and Lassen Peak (8 miles).
  3. Devastated Area to Lassen Peak (12 miles).
 
A bulldozer pushes deep snow off a slope below Emerald Lake on the park highway.
A bulldozer pushes snow off a steep slope below Emerald Lake on the park highway.

What's the Delay?

Clearing the park highway is no quick or easy undertaking! Snow accumulates on the 30-mile park highway throughout the winter season (typically November through April). Snow depth can reach up to 30 feet at the highest elevations, with drifts occasionally reach as high as 40 feet. The road clearing process can take up to three months due to numerous factors including:

  • Heavy snowpack with deeper snowdrifts in some areas

  • Trees and boulders that have fallen across the road and been buried in the snow

  • Rockslides over the highway when the snow begins to melt

  • Snow avalanches over cleared sections of the highway

  • Snow storms (and additional accumulation) during the operations

  • Snow removal in parking areas

  • Road and road shoulder repairs

  • Lingering ice once snow is cleared
  • Equipment repair
 
Visit our keyboard shortcuts docs for details
Duration:
4 minutes, 27 seconds

See how park road crews clear snow from the park highway in a two-month long process each spring.

 

Spring Road Opening Dates - 1980 to Present

Year

Date plowing began from southwest

Date road opened

April 1 Snow Depth at Lake Helen (8,200' elevation)

Date road closed

1980 April 20 May 29 231" / 19.3' November 21
1981 April 20 May 21 149" / 12.5' November 3
1982 April 19 June 18 266" / 22.2' October 25
1983 April 18 July 2 331" / 27.6' November 10
1984 April 23 June 4 175" / 14.6' October 28
1985 April 14 May 18 163" / 13.6' October 21
1986 April 7 June 7 195" / 16.3' November 24
1987 April 20 May 15 138" / 11.6' November 13
1988 April 2 May 20 98" / 8.2' November 7
1989 April 3 June 6 223" / 18.6' October 23
1990 April 1 April 28 106" / 8.9' November 14
1991 April 7 May 24 151" / 12.6' October 22
1992 April 6 May 14 127" / 10.6' October 29
1993 April 12 June 28 225" / 18.8' November 10
1994 April 3 May 20 101" / 8.4' November 7
1995 March 19 July 21 287" / 23.9' November 21
1996 April 1 June 12 171" / 14.3' October 18
1997 April 7 June 5 135" / 11.3' November 14
1998 April 5 July 12 250" / 20.9' November 10
1999 April 12 June 11 194" / 16.2' November 19
2000 April 3 June 2 178" / 14.9' November 17
2001 April 2 May 10 109" / 9.1' November 15
2002 April 1 May 22 166" / 13.9' November 13
2003 March 26 May 23 185" / 15.5' November 7
2004 March 11 May 27 187" / 15.6' October 28
2005 April 4 June 2 173" / 14.5' November 8
2006 April 3 July 6 266" / 22.2' November 11
2007 April 2 May 18 112" / 9.3' December 6
2008 March 31 May 18 132" / 11' December 12
2009 April 13 June 4 146" / 12.2' November 18
2010 April 19 July 8 169" / 14.1' October 23
2011 April 19 July 16 242" / 20.2' November 22
2012 April 21 June 1 145" / 12.1' November 19
2013 March 21 May 24 140" / 11.7' December 18
2014 April 3 May 19 122" / 10.2' December 1
2015 March 31 May 3 91" / 7.6' November 8
2016 April 18 June 12 199" / 16.6' October 30
2017 April 4 July 26 243" / 20.3' November 10
2018 March 30 May 27 131" / 11' November 20
2019 April 18 June 22 238" / 19.8' November 29
2020 March 19 May 29 119" / 10' November 13
2021 April 5 114.5" / 9.5'

Last updated: April 9, 2021

Contact the Park

Mailing Address:

PO Box 100
Mineral, CA 96063

Phone:

(530) 595-4480

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