Summary 
| Difficulty | 4 Intermediate-advanced |
| Length | 14.2 miles round trip |
| Starting Elevation |
6750 feet |
| Cumulative Elevation Change |
+2100, -2100 round trip |
| Navigation | Road and map |
| Time | Full day |
| Season | December through April |
| Snowmobiles Use | Not permitted [Please report illegal use of snowmobiles in this area.] |
| USGS Topo | 7.5' series, Lassen Peak, Reading Peak |
| Start | Kohm Yah-mah-nee Visitor Center located one mile past the Southwest Entrance Station. |
Description
Bumpass Hell is a basin tightly surrounded by ridges on three sides, and filled with bubbling mud pots, steaming fumaroles, and colorful pools. Since it is Lassen Park's most active hydrothermal area, hundreds of park visitors visit it daily during the summer months. During the winter months, however, you will find the area free of all but the hardiest cross-country skiers.
Although the one-day tour to Bumpass Hell is relatively long, 12.4 of the miles (round trip) are on Lassen Park Road. The Sulphur Works Cutoff tour can be used to reduce the length of the tour by 2.1 miles in each direction. If you are spending a night or two near Lake Helen, the tour to Bumpass Hell becomes a short day tour.
While the first 6.2 miles of the tour are on a road, in the last mile you must ascend a slope which is often icy due to its northern exposure, and then descend a moderately steep slope to Bumpass Hell.
The tour described here does not follow the summer hiking trail; the summer trail is not a good ski route.
Mileage Log
Numbers in parentheses
correspond to mileage points on map
Waypoint 1 to 2
Miles: 0.0 - 0.7
Elevation change: +200
From the trailhead (1) ski north on Lassen Park Road for 0.7 mile until you reach the bridge (2) across West Sulphur Creek. The bridge is the turnoff point for Ridge Lakes tour.
Waypoint 2 to 3
Miles: 0.7 - 0.8
Elevation change: +50
Ski northeast on Lassen Park Road for 0.1 mile until you reach the Sulphur Works (3). At the Sulphur Works, an active hydrothermal area, you can hike the short nature trail (boardwalks) located on the north (left) side of the road. The Sulphur Works Cutoff tour also begins here. The cutoff shortens the tour to Emerald Lake and Lake Helen by 2.1 miles and bypasses the portion of Lassen Park Road east of Diamond Peak that is prone to avalanche.
Waypoint 3 to 4
Miles: 0.8 - 1.5
Elevation change: +150
Ski southeast on Lassen Park Road for 0.7 mile until you reach Brokeoff Mountain Viewpoint (4). The viewpoint, also called Windy Point, offers an excellent view to the west of Brokeoff Mountain, the largest remaining part of Mt. Tehama, an 11,000-foot volcano.
Waypoint 4 to 5
Miles: 1.5 - 2.1
Elevation change: +150
Ski generally east on Lassen Park Road for 0.6 mile until you reach Diamond Point (5). Diamond Point affords a good view to the southeast of the Mill Creek drainage and Mt. Conard.
Waypoint 5 to 6
Miles: 2.1 - 3.5
Elevation change: +350
Ski north on Lassen Park Road for 1.1 miles to a 180 degree turn in the road and then for 0.3 mile until you reach Diamond Peak Saddle (6). The saddle is located at the top of an S-turn where the road travels along a ridge-like area. The Sulphur Works Cutoff intersects the road 0.1 mile past here.
Waypoint 6 to 7
Miles: 3.5 - 5.3
Elevation change: +500
Ski north on Lassen Park Road for 0.8 mile until you reach the start of an S-turn, then ski 0.3 mile through the S-turn, and then generally east for 0.7 mile until you reach Emerald Lake (7). Emerald Lake is the first good snow camping site along Lassen Park Road.
Waypoint 7 to 8
Miles: 5.3 - 5.9
Elevation change: +50
Ski east on Lassen Park Road for 0.6 mile until you reach Lake Helen (8). If you lose sight of the road at Emerald Lake, ski east until you reach Lake Helen where you will be able to pick up the road again.
Waypoint 8 to 9
Miles: 5.9 - 6.2
Elevation change: +150
Ski generally east on Lassen Park Road for 0.3 mile until you reach the location where the road turns north (left) (9). The turn in the road is the turnoff point for the Bumpass Hell tour and the start of the Lake Helen Cutoff tour that shortens the tour on the park road by 3.1 miles.
Waypoint 9 to 10
Miles: 6.2 - 6.4
Elevation change: +100
Leave the road and climb southeast for 0.2 mile until you reach a saddle (10).
Waypoint 10 to 11
Miles: 6.4 - 6.6
Elevation change: +150
Traverse and climb southwest for 0.2 mile until you reach a plateau (11). The route from the pass to the plateau is relatively obvious because it is the most gradual. However, this north-facing slope can get very icy and you should exercise appropriate care to avoid the possibility of a fall which would carry you down to the steeper slopes.
Waypoint 11 to 12
Miles: 6.6 - 6.9
Elevation change: -150
Continue skiing southwest across the plateau and then descending for a total of 0.3 mile until you reach the point where the slope gets noticeably more steep (12).
Waypoint 12 to 13
Miles: 6.9 - 7.1
Elevation change: -150
Descend southeast for 0.2 mile until you reach Bumpass Hell (13). Please stay on the boardwalks or snow-covered areas at Bumpass Hell.
Return to trailhead
Miles: 7.1 - 14.2
Elevation change: +300, -1800
Retrace the route for 7.1 miles back to the trailhead (1).
