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Avalanche Advisory for 2017-04-01 06:43:52

  • EXPIRED ON April 2, 2017 @ 6:43 am
    Published on April 1, 2017 @ 6:43 am
  • Issued by Andrew Kiefer - Mt Shasta Avalanche Center

LOW avalanche danger exists at all elevations, and Normal Caution is advised. Extreme northerly winds have scoured most snow surfaces over the past 48 hours, and strong north winds will continue today above 10000ft. Warm temperatures and intense solar radiation will create a significant falling rime ice hazard in the alpine on Mount Shasta.  Also, watch for isolated wet loose avalanches on steep sun exposed slopes as it warms up throughout the day.

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Forecast Hotline: (530) 926-9613

Avalanche Problem 1: Normal Caution

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Avalanches are unlikely throughout the advisory area, and any avalanche event would likely be small.  As temperatures increase throughout the day and the solar radiation intensifies, the greatest objective hazard will be falling rime ice in the alpine on Mount Shasta.  In addition, the potential for isolated wet loose avalanche activity exists on sun exposed slopes steeper than 35 degrees.  Watch for falling rime ice if you venture high on the mountain this weekend.  Also, monitor the snow surface as it warms up throughout the day.  Watch for pinwheels and roller balls, and avoid steep slopes where the snow surface has become wet and unconsolidated.

Forecast Discussion

Warm spring weather is expected today, although challenging windy conditions will likely continue at upper elevations on Mount Shasta.  The recent snow from Thursday, paired with strong northerly winds, created a shallow wind slab problem yesterday that was short lived.  The extreme winds were much more effective in scouring snow surfaces than loading snow to form wind slabs, and no signs of a significant wind slab problem were observed during a tour in Avalanche Gulch yesterday. 

With warm temperatures and sunny skies expected for the morning and early afternoon, loose wet avalanches could become a concern on steep sun exposed slopes.  The winds will likely minimize the potential for loose wet activity, as will increasing cloud cover throughout the day. As conditions in the advisory area continue to transition from winter to spring, wet loose avalanche activity and falling rime ice should be expected.  Anticipate these hazards and plan your day accordingly.

Recent Observations

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Northerly winds were the driving factor on Mount Shasta yesterday.  From 7-11am, steady 30-40mph winds were observed in Avalanche Gulch between Horse Camp and Lake Helen.  Estimated gusts ranged from 60-80mph, and uphill travel against the downslope winds was a loosing battle.  By noon, the winds diminished significantly below 8000ft, but continued above.

Snow surfaces were variable.  The recent snow from Thursday was cold and dry, but was significantly affected by the wind.  Only protected gully features held wind deposits, while the wind scoured nearly all other snow surfaces at and above 7500ft.  Skies were clear and sunny and temperatures were above freezing.  Snow surfaces softened by the early afternoon up to 9000ft.  The new snow became very sticky and heavy below treeline as the day progressed.  Slick and scoured surfaces allowed for a brief window of corn-like skiing before becoming sloppy by the afternoon. 

Weather and Current Conditions

Weather Summary

A ridge of high pressure is in place, and will allow for mostly dry and clear weather through the weekend.  Skies will be mostly sunny this morning with increasing cloud cover building this afternoon and overnight.  No precipitation is expected.  Strong northerly winds will continue above the 10000ft level on Mount Shasta, and high temperatures for the day will reach the mid 50’s F at the 6000ft level.  Tomorrow looks to bring similar conditions with clear and sunny weather in the morning, and increasing clouds again in the afternoon. 

In Mt Shasta City at 0500, we have a current temperature of 45 F

On Mt Shasta (South Side) in the last 24 hours...

Sand Flat - 6,750 ft, the current temperture is 30 degrees F. Temperatures have ranged from 17 F to 31 F. Snow on the ground totals 108 inches with a trace of new snow and 4 inches of settlement.

Old Ski Bowl - 7,600ft. This weather station is down. We apologize for the inconvenience.

Grey Butte - 8,000 feet, the current temperature is 40 degrees F. Temperatures have ranged from 15 F to 40 F. Winds have averaged 15-20mph mph with gusts to 42 mph, and have transitioned from northerly southeasterly in direction.

Mt Eddy Range (West side of Interstate-5)... 

Castle Lake - 5,800 feet, the current temperature is 37 degrees F. Temperatures have ranged from 23 F to 46 F. Snow on the ground totals 98 inches with no new snow and 1 inch of settlement.

Mt Eddy - 6,500 feet, the current temperature is 42 degrees F. Temperatures have ranged from 21 F to 42 F. Snow on the ground measures 92 inches with no new snow and 1 inch of settlement. Winds have averaged 2-5 mph with gusts up to 14 mph, blowing SE and SW.

THIS SEASON PRECIPITATION for MT SHASTA CITY: Since October 1st (the wet season), we have received 49.46 inches of water, normal is 35.46 inches, putting us at 139% of normal. For the month of March, we have received 6.15 inches of water, normal is 5.96 inches, which is 103% of normal. And finally for the year of 2017, we received 28.30 inches of water, normal is 20.25 inches, putting us at 140% of normal.

Always check the weather before you attempt to climb Mt Shasta. Further, monitor the weather as you climb. Becoming caught on the mountain in any type of weather can compromise life and limb. Be prepared.

 

CURRENT CONDITIONS at Bunny Flat (6950 ft)
Weather Station Map
Weather Station Table
0600 temperature: 30
Max. temperature in the last 24 hours: 31
Average wind direction during the last 24 hours: southeast
Average wind speed during the last 24 hours: 15 mi/hr
Maximum wind gust in the last 24 hours: 40 mi/hr
New snowfall in the last 24 hours: trace inches
Total snow depth: 108 inches

Two Day Mountain Weather Forecast

Produced in partnership with the Medford NWS

For 7000 ft to 9000 ft
  Saturday
(4 a.m. to 10 p.m.) 		Saturday Night
(10 p.m. to 4 a.m.) 		Sunday
(4 a.m. to 10 p.m.)
Weather Mostly Sunny Partly Cloudy Mostly sunny.
Temperature (°F) 53 34 45
Wind (mi/hr) North 8-18 mph North 8 mph North 7 mph
Precipitation SWE / Snowfall (in) / 0 / 0 / 0
For 9000 ft to 11000 ft
  Saturday Saturday Night Sunday
Weather Mostly Sunny and Windy Partly Cloudy and Windy Mostly Sunny and Windy
Temperature (°F) 32 24 24
Wind (mi/hr) North 23-42 mph, Gusting to 48 mph North 0 Northwest 28-38 mph, Gusting 55
Precipitation SWE / Snowfall (in) / 0 / 0 / 0

Disclaimer

This advisory 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 advisory expires on midnight of the date it was posted unless otherwise noted.