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Avalanche Forecast for 2020-04-04 06:20

  • EXPIRED ON April 5, 2020 @ 6:20 am
    Published on April 4, 2020 @ 6:20 am
  • Issued by Nick Meyers - Shasta-Trinity National Forest

A robust spring storm will impact the mountains over the next 48 hours. Southerly flow will bring periods of heavy precipitation and windy conditions. Avalanche risk will increase as new snow begins to accumulate and strong wind impacts alpine terrain. New snow will rest on top of smooth, firm bed surfaces. Natural and human triggered avalanches are increasingly likely as we move through the weekend. Mindful terrain choice is of vital importance. Please, be safe.

Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Avalanche Problem 1: Wind Slab

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Strong winds out of the south/southwest will gradually increase today along with new snow. Near and above treeline will experience active wind loading. Those aspects on the top half of the compass will be the most dangerous. Don't rule out other aspects and cross-loading too. People, you must pay attention this weekend. Avoid all wind loaded slopes steeper than 30 degrees. Seek out those small test slopes and stomp on them. If you see small slabs, shooting cracks or perhaps hear some whoomphing, you could be entering the danger zone. The safest bet? Avoid avalanche terrain as this weekend's storm builds.

Avalanche Problem 2: Storm Slab

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For the beginning of this weekend's weather cycle, storm slabs will be of low concern. If and when you observe more than 6 inches of fresh snow on top of our existing, smooth and firm bed surfaces,  you'll need to be mindful for storm slab avalanches. This type of avalanche is found in below treeline and protected, near treeline areas. Ski cut results on small, inconsequential slopes or natural activity on indicator slopes are often the best clues a storm slab problem exists. As the avalanche risk increases this weekend, mindful terrain choice will be imperative.

Forecast Discussion

                                                           COVID-19 Information - Updated 4.3.2020 

A state wide shelter-in-place order exists for ALL citizens. It is critical that we comply with this order. We recommend exercising close to home and complying with local and state guidance. We know what you're thinking...fresh snow in the mountains, let's go! It makes us cringe to say "locals only", but perhaps now is the time. Please, do no travel for your recreation needs. 

At the Mount Shasta Avalanche Center, we always encourage people to get information before planning or heading out for a day in the backcountry. We emphasize that you need to match your plan to the current conditions. Usually, we talk about current snow, weather and avalanche conditions. These are not usual times: now, you need to think about public health conditions.

If you choose to recreate in the mountains, remember your actions may impact others. Please enjoy the backcountry safely, and keep our communities, medical and emergency services professionals, and fellow backcountry users in mind when you consider your terrain choices.

Recent Observations

  • In the last 24 hours, temperatures at treeline have ranged from 14 to 35 deg F.
  • We've received no new snow
  • Wind average 10 mi/hr with gusts to 25 mi/hr at 8,000 feet, west/northwest
  • Minor roller balls and surface sloughing on protected, sunny east and south aspects below and near treeline
  • Grey Rocks (Sacramento drainage) snow survey course yielded average height of snow of 57" with 21.5" SWE (snow/water equivalent)
  • Snow surfaces are smooth and firm. Solar aspects softened early afternoon
  • Most lakes are still frozen. Tree wells are showing. Small streams are running and exposed.

Weather and Current Conditions

Weather Summary

A winter storm warning is in effect until 5PM PDT Sunday. We're off to a slow start, but this morning we are staring down the barrel of a stormy weekend expected to bring just over 2 inches of precipitation to the area. Southerly flow may provide for periods of heavy precipitation. While snow levels are expected to sit just above 4,000 feet, we could see snow to town. Being it's April, impacts at lower elevations will be minimal. On the mountain however, it's going to be wintry. Strong southerly wind will combine with ample snowfall and we could see 1-2 feet of new snow by next week. Dry conditions will return through the end of next week.

24 Hour Weather Station Data @ 4:00 AM

Weather Station Temp (°F) Wind (mi/hr) Snow (in) Comments
Cur Min Max Avg Avg Max Gust Dir Depth New Water Equivalent Settlement
Mt. Shasta City (3540 ft) 33 29 55 40 3 N
Sand Flat (6750 ft) 26 14 37 28 48 0 0 1
Ski Bowl (7600 ft) 24 14 35 26 80.8 0 0 .3
Gray Butte (8000 ft) 22 15.5 34 25 10 25 WNW
Castle Lake (5870 ft) 29 21 42 32 39.3 0 .5
Mount Eddy (6509 ft) 27.5 18 35 27.5 2 10 WSW 57.8 0.2 .6
Ash Creek Bowl (7250 ft) down
Ash Creek Ridge (7895 ft) down

Two Day Mountain Weather Forecast

Produced in partnership with the Medford NWS

For 7000 ft to 9000 ft
  Saturday
(5 a.m to 11 p.m.)
Saturday Night
(11 p.m. to 5 a.m.)
Sunday
(5 a.m to 11 p.m.)
Weather Snow. Slight chance of thunderstorms this afternoon with small hail. Snow level near 4,100 feet. Snow. Snow level near 4,500 feet. Snow. Breezy. Scattered thunderstorms possible. Snow level near 4,400 feet.
Temperature (°F) 29 27 29
Wind (mi/hr) South 10-15 South 10-15 South 10-15
Precipitation SWE / Snowfall (in) 0.47 / 3-6 0.55 / 3-7 0.70 / 4-10
For 9000 ft to 11000 ft
  Saturday Saturday Night Sunday
Weather Snow. Some thunder is also possible. Windy. Snow. Windy. Snow. Some thunder also possible. Windy.
Temperature (°F) 18 13 14
Wind (mi/hr) Southwest 20-30 Southwest 30-40 South 30-40
Precipitation SWE / Snowfall (in) 0.47 / 5-9 0.55 / 7-11 0.70 / 9-13

Season Precipitation for Mount Shasta City

Period Measured (in) Normal (in) Percent of Normal (%)
From Oct 1, 2020 (the wet season) 15.17 35.81 42
Month to Date (since Oct 1, 2020) 0.00 0.35 0
Year to Date (since Jan 1, 2020) 6.24 20.60 30

Disclaimer

This forecast does not apply to Ski Areas or Highways and is for the Mt. Shasta, Castle Lake and Mt. Eddy backcountry. Use this information for guidance only. You may find different conditions in the backcountry and should travel accordingly. This forecast expires 24 hours after the posted time unless otherwise noted.