Spring Road Clearing

2011 Road opening
Rotary plow at the southwest entrance

NPS Photo

Road Opening Process

The park highway will open to through traffic once the final section between Bumpass Hell and Devastated Area is cleared, rockfalls are cleared, and all lingering ice is melted. The road opening process may be delayed by late snow storms as well as other factors including:
  • Heavy snowpack with deeper snowdrifts in some areas
  • Trees 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 during the operations
  • Lingering ice once snow is cleared

2018 Road Clearing Operator Log

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

March 31 - Snow clearing began at Loomis Plaza, moving toward Devastated Area. Plows reached Hot Rock and are beginning to encounter some trees in the road.

April 7 - Snow has been cleared to the Devastated Area, about 10 miles form the Loomis Plaza. Snow clearing progress has moved steadily to the Devastated Area due to the low snow levels, only about 2 feet at the Devastated Area. We will proceed with clearing operations from the southwest entrance on Monday April 9.

April 14 - Road clearing operations began ahead of schedule on the south side of the park this week this week. Road crews have plowed roughly 3 miles of park highway from the Kohm Yah-mah-nee Visitor Center in the southwest corner of the park. On the north side of the park, crews continue to work on clearing the parking area and bathrooms at the Devastated Area.

April 21 - Operations were slowed this week due to a shortage of staff. Another half-mile of road has been cleared bringing the crew to the upper switchback before Emerald Sidehill. We are about 5 miles in from the Visitior Center. Operations will resume on Monday.

Thanks to help from CalTrans, about a foot of snow from Monday's storm was removed from the road. The road opened to the Devastated Area from the northwest entrance at Manzanita Lake!

April 28 - While CalTrans continues to move along steadily from the north, our road crew has made progress from the south to the Bumpass Hell Parking area, about another mile from last week. Clearing opeartions will resume on Tuesday as will clearing on the road into Juniper Lake.

May 5 - The big event this week was a large rock fall, covering the entrie width of the road in the Emerald Lake Area. Fortunately, no equipment or people were harmed. As snow melts exposing bare ground, freeze and thaw cycles break rock loose along along steep slopes. Rockfall this time of the year is not uncommon. Use extreme caution when traveling the road by vehicle, or on foot.
Otherwise, clearing progressed to the Kings Creek Area from the north. From the south, clearing progressed another half-mile to Lake Helen.

May 12 - Clearing has progressed to just north of the road's summit at 8,500 feet. Clearing was delayed somewhat due to last week's rockfall which blocked the entire width of the road. Boulders the size of cars fell, so it took a couple of days to clear one lane. Further assesment for slope stability will need to happen before traffic will be permitted. Snow was removed from the Juniper Lake road, however a thick layer of ice remains and will need to soften before clearing can continue in order to prevent damage to the road's surface. This will be attempted next week. Cal Trans will continue to help with clearing snow form the Lassen Peak Parking lot on Monday.

May 19 - The crew broke through on Wednesday the 16th, meeting with the cleared road from the north! There is stil a lot of work to be done before the road can open to vehicles. Summit Lake Campground, Summit Lake Horse Corral, picnic areas, pull-outs and brooming need to be completed. But the hard work is over for this season. The road will open on Sunday, May 27th!
Road clearing on Emerald side hill
Snow plowing below Emerald Lake

NPS Photo

When Will the Highway Open to Through Traffic?

Road clearing operations began on March 31, 2018. Sections of the park highway will open when it is safe and there is sufficient parking for vehicle traffic.

The park highway encompasses 30 miles of stunning views through twisty hair pin corners, high elevations and steep grades. To attempt road clearing throughout winter would be impossible and extremely hazardous for plow operators and drivers. The park highway traverse avalanche prone slopes with up to 2,000 foot drops and can hold a snowpack up to 40 feet deep. With the park's high elevation and exposed passes, ice and blowing snow would be a constant issue.

Clearing of the park highway usually begins in April and continues for about two months before the road opens to through traffic. Predicting when the road will open is not possible, even in late spring, because weather in April and May can affect plowing progress significantly. See the chart below for opening and closing dates since 1980.


Spring Road Opening Dates - 1980 to Present


Date plowing began from southwest

Date road opened

Date road closed

1980 April 20 May 29 November 21
1981 April 20 May 21 November 3
1982 April 19 June 18 October 25
1983 April 18 July 2 November 10
1984 April 23 June 4 October 28
1985 April 14 May 18 October 21
1986 April 7 June 7 November 24
1987 April 20 May 15 November 13
1988 April 2 May 20 November 7
1989 April 3 June 6 October 23
1990 April 1 April 28 November 14
1991 April 7 May 24 October 22
1992 April 6 May 14 October 29
1993 April 12 June 28 November 10
1994 April 3 May 20 November 7
1995 March 19 July 21 November 21
1996 April 1 June 12 October 18
1997 April 7 June 5 November 14
1998 April 5 July 12 November 10
1999 April 12 June 11 November 19
2000 April 3 June 2 November 17
2001 April 2 May 10 November 15
2002 April 1 May 22 November 13
2003 March 26 May 23 November 7
2004 March 11 May 27 October 28
2005 April 4 June 2 November 8
2006 April 3 July 6 November 11
2007 April 2 May 18 December 6
2008 March 31 May 18 December 12
2009 April 13 June 4 November 18
2010 April 19 July 8 October 23
2011 April 19 July 16 November 22
2012 April 21 June 1 November 19
2013 March 21 May 24 December 18
2014 April 3 May 19 December 1
2015 March 31 May 3 November 8
2016 April 18 June 12 October 30
2017 April 4 July 26 November 10
2018 March 30

Last updated: June 19, 2018

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Mailing Address:

PO Box 100
Mineral, CA 96063


(530) 595-4480

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