The last avalanche forecast for the 2023-2024 season posted on April 21st. Thank you to all who contributed to the avalanche center this season through observations, volunteer time, and/or financial contributions.
This Avalanche Advisory was published on January 7, 2009:
January 7, 2009 at 7:57 am | |
This morning the avalanche danger is LOW for all aspects and elevations. Pockets of MODERATE danger could develop on sun exposed SE-S-SW-W aspects steeper than 35 degrees by this afternoon. |
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Forecast Discussion:
Last night air temperatures stayed above freezing due to a high pressure system over the forecast area. This high pressure will cause sunny skies and warm temperatures to continue today. Northwest winds associated with this system should continue before shifting to the west ahead of a small low pressure forecasted to move through the area tomorrow. This low should bring cooler temperatures and a chance for up to 2 inches of snow at the higher elevations tomorrow afternoon.
Observations from Mt. Tallac and the Mt. Rose area yesterday showed a mostly stable snowpack. Bonds within and between layers in the snowpack continue to gain strength. A mix of sun crusts on southerly aspects, wind crusts on northerly aspects, and some unconsolidated snow on protected northerly aspects exists on the the snow surface. By yesterday afternoon 2-3 inches of wet surface snow formed on sun exposed areas across all aspects up to 8500'. Clear skies overnight should have allowed this wet surface snow to refreeze.
As sun and warmth melt the snow surface today, free water will dissolve the bonds within the upper snowpack. This melting process could weaken the snowpack enough for human triggerable wet snow instabilities to form on steep sun exposed SE-S-SW-W aspects. Most of these instabilities should be in the form of point release avalanches and surface instabilities like pinwheels. Areas around rocks, trees and other exposed objects will be the most susceptible to these instabilities. In these areas some small pinwheels and wet snow sluffs could occur naturally. Last night's refreeze, moderate north winds, and the weak January sun should prevent wet snow instabilities from becoming large or widespread and should keep significant natural avalanche activity unlikely today.
The bottom line:
This morning the avalanche danger is LOW for all aspects and elevations. Pockets of MODERATE danger could develop on sun exposed SE-S-SW-W aspects steeper than 35 degrees by this afternoon.
Weather Observations from along the Sierra Crest between 8200 ft and 8800 ft:
0600 temperature: | 40 deg. F. |
Max. temperature in the last 24 hours: | 42 deg. F. |
Average wind direction during the last 24 hours: | Northeast to northwest |
Average wind speed during the last 24 hours: | 15-20 mph |
Maximum wind gust in the last 24 hours: | 49 mph |
New snowfall in the last 24 hours: | O inches |
Total snow depth: | 63 inches |
Two-Day Mountain Weather Forecast - Produced in partnership with the Reno NWS
For 7000-8000 ft: |
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Wednesday: | Wednesday Night: | Thursday: | |
Weather: | Sunny | Clear | Mostly cloudy with a chance of snow in the afternoon |
Temperatures: | 44-51 deg. F. | 33-38 deg. F. | 30-35 deg. F. |
Wind direction: | Northwest | Southwest | Southwest shifting to the west |
Wind speed: | 10 mph | 10-20 mph | 15-30 mph with gusts to 45 mph |
Expected snowfall: | O in. | O in. | up to 1 in. |
For 8000-9000 ft: |
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Wednesday: | Wednesday Night: | Thursday: | |
Weather: | Sunny | Clear | Mostly cloudy with a chance of snow in the afternoon |
Temperatures: | 40-46 deg. F. | 30-35 deg. F. | 30-39 dropping to 20-25 deg. F. |
Wind direction: | Northwest | West | West |
Wind speed: | 10-20 mph with gusts to 30 mph | 10-20 mph with gusts to 30 mph increasing to 15-25 mph with gusts to 50 mph after midnight | 30-45 mph with gusts to 70 mph. Ridgetop gusts to 95 mph |
Expected snowfall: | O in. | O in. | up to 2 in. |