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 area of high pressure over the region will further weaker over the next few days allowing for a multi day cooling trend to occur. Weather systems passing to the north of the forecast area will continue to provide and mix of clouds and sun. Remote sensors above 8,000' are reporting temperatures this morning in the upper 30s to mid 40s. This is about 3 to 5 degrees colder than 24 hours ago for most locations. Forecast maximum daytime air temperatures for today are expected at 7 to 10 degrees colder than the past two days. Ridgetop winds remain out of the southwest this morning and are moderate in speed. Moderate speed winds out of the southwest to west are forecast to continue tonight and tomorrow.

Recent Observations:

Observations made yesterday on Tamarack Peak (Mount Rose area) continued to show a trend of stabilizing persistent weak layers. Snowpit data collected near the site of the March 9 snowboarder triggered avalanche (photos, more info) and snowpit data collected in this area on March 11 indicated that triggering a persistent slab avalanche in this area has become unlikely (video, pit profile, more info). This weak layer of near crust facets remains at the base of the recent storm snow and may return to the state of an active weak layer in the future. This is consistent with snowpit data collected three days ago on Silver Peak (Pole Creek area) targeting this same weak layer (video, more info). Data collected two days ago on Schallenberger Ridge at the site of the skier triggered avalanche on March 10 indicated that the weak layer had changed significantly in this lower elevation area and would not likely show instability in the future (video, more info).

Despite thick cloud cover and moderate speed SW winds for most of the morning hours in the Tamarack Peak area, 2 to 3 inches of wet surface snow existed on all aspects below 9,500' at noon. Wet snow instability was limited to skier triggered roller balls at the time. At the rate of melt, more significant wet snow instability was likely to form during the mid and late afternoon hours.

Avalanche Problem #1: Loose Wet Avalanches

Air temperatures are colder this morning than yesterday morning and forecast maximum daytime air temperatures are colder than the past two days. As a result, the amount of wet surface snow and subsequent instability that forms today is expected to be less than what occurred over the past two days. Human triggered roller balls, pinwheels, and loose wet avalanches are expected to form again today. Areas of wet snow instability are expected to form a little more slowly today than yesterday and not involve as much snow.

Avalanche Problem #2: Persistent Slabs

Observations made over the past three days have indicated that triggering a persistent slab avalanche has become unlikely. For the most part, triggering has become difficult, but weak layer and overlying slab characteristics show that propagation remains possible. Where this near crust facet weak layer exists at the base of the recent storm snow on NW-N-NE aspects should not be forgotten. Concerns surrounding this weak layer are now shifting towards reactivation of this weak layer under future new snow loading conditions. There is a significant storm event in the weather forecast for March 19 and 20. If this weather forecast verifies and the storm event comes to fruition, a persistent deep slab avalanche cycle could occur.

The bottom line:

Early this morning, avalanche danger is LOW for all elevations and aspects. Pockets of MODERATE avalanche danger will form today both above and below treeline on all aspects on slopes 35 degrees and steeper in response to daytime warming. As snow surface melting progresses, human triggered loose wet avalanches will become possible.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	37 to 44 deg. F.
Max. temperature in the last 24 hours:	47 to 57 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	27 mph
Maximum wind gust in the last 24 hours:	35 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	53 to 84 inches

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

For 7000-8000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Partly cloudy skies.	Partly cloudy skies.	Partly cloudy skies.
Temperatures:	47 to 54 deg. F.	25 to 32 deg. F.	44 to 51 deg. F.
Wind direction:	SW	SW	W
Wind speed:	10 to 15 mph with gusts to 25 mph in the afternoon.	15 to 20 mph with gusts to 30 mph.	15 to 20 mph with gusts to 30 mph.
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Friday:	Friday Night:	Saturday:
Weather:	Partly cloudy skies.	Partly cloudy skies.	Partly cloudy skies.
Temperatures:	45 to 51 deg. F.	29 to 35 deg. F.	43 to 49 deg. F.
Wind direction:	SW	W	W
Wind speed:	15 to 25 mph with gusts to 35 mph.	15 to 25 mph with gusts to 35 mph.	15 to 25 mph with gusts to 35 mph.
Expected snowfall:	O in.	O in.	O in.