This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

The low pressure system off the coast of CA has begun moving inland bringing precipitation and cloud cover with it. This morning the precipitation should reach the Sierra. Since the track of this storm remains more southerly, areas south of Echo Summit should see the most precipitation with three to six inches of snow possible in the next 24 hours. North of Echo summit and east of the Lake the forecast calls for significantly less precipitation with only one to three inches of snowfall. Temperatures should remain cool with high's today and tomorrow in the upper 20's and low 30's above 7000 ft. The winds should shift to the southwest and increase today as the low pressure moves through the area then decrease during the night and remain moderate tomorrow.

Recent Observations:

Yesterday tests on the persistent weak layer of sugary snow (facets) near old crusts on Incline Lake Peak (video, more info) and in the Deep Creek (videos, more info) area still indicated still that it remains weak and that fractures can easily travel through this layer if it breaks. On Incline Lake Peak four to five feet of strong snow remained on top of this layer making it very difficult for people on the surface to trigger a fracture in the deeply buried layer. In the Deep Creek area at lower elevations, only two to three feet of snow existed on top of this weak layer. In both of these areas a mix of supportable and breakable crusts with a trace of new snow on top existed on snow surface of the northerly aspects. Below this crust in the Deep Creek area recent warming had allowed the entire snowpack to become moist. On the southerly aspects of Incline Lake Peak a frozen melt-freeze crust existed above 8600 ft. Below that elevation about one half to one inch of soft melt-freeze snow had formed on the surface by noon.

Today's Primary Avalanche Concern: Wind Slabs

The new snow and wind forecasted to occur today could create new small wind slabs similar to those that formed on March 23. These shallow slabs should only exist on the most heavily wind loaded N-NE-E aspects and cross-loaded SE aspects in isolated areas in some near and above treeline terrain. Areas south of Echo Summit could see larger wind slabs form due to more snow accumulation. Even though human triggering of these slabs should become possible today, they should not entrain enough snow to bury a person due to their shallowness. These small slides could knock a person off balance or push them into a terrain trap that could magnify the consequences of a small slide.

Today's Secondary Avalanche Concern: Persistent Deep Slabs

Transmitting enough force through the snowpack to trigger a deep slab avalanche remains very difficult due to the depth of the weak layer and the strength of the slab above it. However, if this layer does break, tests indicate that large destructive avalanches with serious consequences could still result. These kind of avalanches will remain possible today on NW-N-NE aspects at all elevations. Areas with a shallow snowpack, areas near exposed rock outcrops and cliffs, steep unsupported slopes, complex terrain features, and slopes with trigger points represent some locations where the persistent weak layer could remain closer to the surface allowing for the possibility that people on the surface could initiate a fracture. That fracture could then propagate out into much deeper parts of the snowpack. Larger triggers like large cornice failures or other avalanches could also produce these deep slab avalanches today.

The bottom line:

On slopes 35 degrees and steeper, pockets of MODERATE avalanche danger exist both above and below treeline on NW-N-NE aspects and on near and above treeline E-SE aspects due to ongoing persistent deep slab instability and some new shallow wind slabs. Large destructive deep slab avalanches remain possible. For all other areas, avalanche danger is generally LOW.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

Weather Observations from along the Sierra Crest between 8200 ft and 8800 ft:

0600 temperature:	24-31 deg. F.
Max. temperature in the last 24 hours:	36-45 deg. F.
Average wind direction during the last 24 hours:	South
Average wind speed during the last 24 hours:	20-30 mph
Maximum wind gust in the last 24 hours:	45 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	40-78 inches

Two-Day Mountain Weather Forecast - Produced in partnership with the Reno NWS

For 7000-8000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Cloudy with periods of showers in the morning. Snow showers decreasing in the afternoon.	Cloudy with snow likely.	Mostly cloudy with a chance of snow showers
Temperatures:	31-39 deg. F.	13-20 deg. F.	31-39 deg. F.
Wind direction:	South	West	Southwest
Wind speed:	15-20 mph with gusts to 35 mph	10-15 mph with gusts to 25 mph becoming light after midnight	10-15 mph with gusts to 25 mph
Expected snowfall:	North of Echo Summit: up to 3 in. | South of Echo Summit: 2-5 in.	up to 1 in.	O in.
For 8000-9000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Cloudy with periods of showers in the morning. Snow showers decreasing in the afternoon.	Cloudy with snow likely.	Mostly cloudy with a chance of snow showers
Temperatures:	26-32 deg. F.	10-17 deg. F.	27-33 deg. F.
Wind direction:	South shifting to southwest in the afternoon	Southwest	Southwest
Wind speed:	40-45 mph with gusts to 65 mph decreasing to 25-30 mph with gusts to 45 mph in the afternoon	20-25 mph with gusts to 35 mph decreasing to 10-15 mph with gusts to 25 mph after midnight	20-30 mph with gusts to 45 mph
Expected snowfall:	North of Echo Summit: up to 3 in. | South of Echo Summit: 2-5 in.	up to 1 in.	O in.