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.

A strong cold front and low-pressure system moving southeast from the Gulf of Alaska should start to push the high-pressure ridge east of the forecast area today. This transition should bring strong southwesterly winds and cooling temperatures to the region. Some cloud cover should start to develop during the day. By tonight scattered snow showers could occur over the forecast area. These showers should continue through tomorrow. However, this cold front does not have much moisture associated with it so snowfall amounts should remain very small.

After another moderate and shallow refreeze on Tuesday night, the snow surface softened quickly yesterday on any sun-exposed slopes. By 10:30 am on Castle Peak, no evidence of a refreeze remained on the E-SE-S-SW-W aspects, and 10-18 inches of wet snow existed on the snow surface. The more northerly aspects remained frozen a little longer and melted to a slightly lesser degree. No avalanche activity was reported yesterday.

Wet snow instabilities will continue to be the main avalanche concern today. Last night temperatures remained above freezing again. However, the clear skies should have allowed the snowpack to radiate enough heat into the atmosphere for a shallow refreeze to occur. The cooler daytime temperatures, increased winds, and more cloud cover should help keep the snow frozen for a little longer today making wet snow instabilities less widespread than yesterday or the day before. Enough melting could still occur due to above freezing air temperatures and the intense April sunshine for some wet snow instabilities to form on sun-exposed slopes. Human-triggered wet point-release avalanches, roller-balls, and pinwheels will remain possible today. The most likely areas for these instabilities will be on steep, sun-exposed, E-SE-S-SW-W aspects. Well established drainage channels that prevent free water from saturating any one layer in the snowpack should keep wet-slab avalanches unlikely. However, they are not impossible especially in areas where the snowpack sits on an impermeable ground surface like a granite slab. Plan to be off of any sun exposed slopes before they get too soft and wet. To help determine when a slope has become unsafe, use observations of surface wet-snow instabilities and simple tests like stepping into the snow (if you sink into wet snow above your ankles it is a good time to move to a different slope).

The bottom line:

This morning, the avalanche danger is LOW for all elevations and aspects. Above treeline on E-SE-S-SW-W aspects and below treeline on W aspects pockets of MODERATE avalanche danger should quickly develop on slopes 37 degrees and steeper in response to daytime warming. Larger areas of MODERATE avalanche danger should develop on slopes 37 degrees and steeper on E-SE-S-SW aspects below treeline.

Andy Anderson - Avalanche Forecaster, Tahoe National Forest

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

0600 temperature:	37-42 deg. F.
Max. temperature in the last 24 hours:	53-58 deg. F.
Average wind direction during the last 24 hours:	Southwest
Average wind speed during the last 24 hours:	35-45 mph
Maximum wind gust in the last 24 hours:	88 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	123 inches

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

For 7000-8000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:	Partly cloudy this morning becoming mostly cloudy this afternoon	Mostly cloudy with a chance for some isolated snow showers	Mostly cloudy with a chance for isolated snow showers in the morning. Scattered snow showers in the afternoon
Temperatures:	47-54 deg. F.	26-31 deg. F.	33-40 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	15-25 mph with gusts to 40 mph in the morning increasing to 25-35 mph with gusts to 55 mph in the afternoon	20-35 mph with gusts to 60 mph	20-30 mph with gusts to 45 mph
Expected snowfall:	O in.	trace in.	trace in.
For 8000-9000 ft:
	Thursday:	Thursday Night:	Friday:
Weather:	Partly cloudy this morning becoming mostly cloudy this afternoon	Mostly cloudy with a chance for some isolated snow showers	Mostly cloudy with a chance for isolated snow showers in the morning. Scattered snow showers in the afternoon
Temperatures:	39-47 deg. F.	24-29 deg. F.	27-34 deg. F.
Wind direction:	Southwest	Southwest	Southwest
Wind speed:	45-65 mph with gusts to 90 mph	40-60 mph with gusts to 90 mph	30-45 mph with gusts to 80 mph decreasing to 65 mph in the afternoon
Expected snowfall:	O in.	trace in.	trace in.