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Avalanche Advisory for 2016-12-31 07:07:41
- EXPIRED ON January 1, 2017 @ 7:07 amPublished on December 31, 2016 @ 7:07 am
- Issued by Andrew Kiefer - Mt Shasta Avalanche Center
Bottom Line
LOW avalanche danger exists on all aspects and elevations and Normal Caution is advised. Watch for unstable snow on isolated features in upper elevation terrain. Natural and human triggered avalanches are unlikely today. Be aware of firm and icy snow surfaces. A slide for life could occur on steep slopes without immediate self-arrest.
Avalanche Problem 1: Normal Caution
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Character ?
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Aspect/Elevation ?
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Likelihood ?CertainVery LikelyLikelyPossible
Unlikely -
Size ?HistoricVery LargeLargeSmall
Recent warm temperatures followed by cooler and windy conditions yesterday and again today, have melted and then refrozen snow surfaces. These events have worked to solidify the snowpack, and very good snowpack stability exists right now. Recently, wind slab avalanches have been unreactive and very isolated in their distribution. However, Normal Caution and LOW danger do not mean the backcountry is free of hazard. Continue to use safe travel practices and be able to identify isolated features of concern.
No matter what time of year or what the avalanche danger is, remember: Don't go into the backcountry until you get the proper gear and training. Ski and ride one at a time in avalanche terrain. Limit the number exposed to a potential avalanche. Don't re-group in avalanche paths or in run out zones! Stay out of harm's way and always work to reduce your exposure to risk. Pay attention to who is below you AND above you. Promote and teach good backcountry etiquette for others to follow... because others WILL follow! We should always strive to hold ourselves to a high standard in the mountains.
Forecast Discussion
Sunny weather, variable skiing and riding surfaces, and good snowpack stability will continue today. A trace to one inch of new snow overnight did little to change the state of conditions in the backcountry. The avalanche concerns remain steady, and Normal Caution is advised. An incoming storm beginning late tonight and tomorrow, and a good chance of precipitation everyday for the next few days will likely bring change. Be sure to pay attention if the weather forecast verifies, and plan your backcountry travels accordingly. Expect very cold temperatures to move into the area by tomorrow and continue through early next week.
Are there any climbers out there? Very smooth and firm conditions exist on many of Shasta's climbing routes. This is a serious issue to consider if you are a novice climber. A slip/fall and failure to self-arrest will quickly result in a long slide for life. Solid self-arrest skills are mandatory.
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LOCAL AREA ROAD, NORDIC, AND SNOWMOBILE PARK STATUS:
The Sand Flat cross country ski trails are in good shape and ready for your cross country skis and snow shoes. These are backcountry routes marked with blue diamonds on trees. Trails are not groomed. Snow shoers, please blaze a parallel trail to cross country skiers staying out of the skin track. These trails can be accessed via the Everett Memorial Highway. Thank you, and enjoy!
The Mt. Shasta Nordic Center is OPEN for the season! Take advantage of this wonderful venue. Groomed trails accomodate both classic and skate skiing styles. Rentals available. Visit their website for more details. http://www.mtshastanordic.org
The Pilgrim Creek & Deer Mountain Snowmobile Parks are open, however there is no snow at these locations currently. One must drive down the 19 road (Military Pass) for several miles to get to consistent snow before unloading. Private industry is logging out there so watch out for log trucks. Head to our "Education" tab on our website and find the snowmobile section for trail information, grooming status, and other sledder resources.
The Castle Lake Road is OPEN. The Everett Memorial Highway is OPEN. The Castle Lake and Everett Hwy are plowed year round to the trailheads. The roads are not always first priority, so your dawn patrol powder mission might be ceased if the plow has not made it up yet. Siskiyou County does a great job keeping the roads clear. Be respectful of the plow drivers if you encounter them. If you get to Bunny Flat before or during when the plow is there, please park on the uphill, LEFT side of the parking lot as you drive in. This is uphill and lookers right of the bathrooms. Thank You!
The Five Red Flags of Avalanche Danger any time of year include: 1) Recent/current avalanche activity 2) Whumphing sounds or shooting cracks 3) Recent/current heavy snowfall 4) Strong winds transporting snow 5) Rapid warming or rain on snow.
Recent Observations
A report of an avalanche on the southeast slopes of Powder Bowl was submitted yesterday. The exact timing of the event is unknown, but the avalanche is at least 2-3 days old. In the observation photos, the height of the crown tapers, and the bed surface has begun to fill in again with transported snow – characteristics of an old wind slab avalanche. It was noted that the avalanche had some wet characteristics, and solar radiation and rapid warming may have been contributing factors.
Snow surface conditions are variable. Wind scoured, firm, and icy conditions are widespread in upper elevation terrain requiring the use of an ice axe and crampons on steep slopes. In lower elevation terrain and on sun-exposed slopes, breakable crust exists. On shady slopes protected from the wind, cold soft snow still remains from the Christmas weekend storm. Throughout our entire advisory area, good coverage exists - 6,500ft and above holds a base of 2-3ft or more.
Weather and Current Conditions
Weather Summary
An upper level, closed low-pressure system has moved through the advisory area and will continue on a southerly track down the California Coast today. Overnight, this closed low allowed for a quick burst of precipitation, and our weather station sites reported .02-.05 inches of water, leaving just a trace to one inch of new snow. Northeasterly flow aloft will be in place over the area, and low-level easterly flow will bring drier and colder conditions. A clearing trend will continue through this evening, and sunny skies are expected today. Highs will be in the mid 30’s with northeast winds blowing 5-10mph, and 40-50mph winds above 9,000ft out of the east.
The next round of precipitation is expected to begin by 4am tomorrow morning. A short wave trough will bring a change to westerly flow. Cold temperatures already in place will allow for 1500ft freezing levels. By the end New Year’s Day, our advisory area has a chance to pick up 3-5 inches of new snow. A progressive weather pattern and very cold temperatures will continue through the first half of next week.
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In Mt Shasta City at 0500, we have a current temperature of 28 F.
On Mt Shasta (South Side) in the last 24 hours...
Old Ski Bowl - 7,600 feet, the current temperature is 28 degrees F. Snow on the ground totals 72 inches with a trace of new snow. Temperatures have ranged from 25 F to 40 F.
Grey Butte - 8,000 feet, the current temperature is 25 degrees F. Temperatures have ranged from 22 F to 37F. Winds have averaged 15-25 mph with gusts to 49 mph, blowing out of the west/northwest shifting to the east/northeast.
Mt Eddy Range (West side of Interstate-5)...
Castle Lake - 5,600 feet, the current temperature is 25 degrees F. Temperatures have ranged from 23 F to 45 F. Snow on the ground totals 26 inches with a trace of new snow.
Mt Eddy - 6,500 feet, the current temperature is 25 degrees F. Temperatures have ranged from 22 F to 43 F. Snow on the ground measures 30 inches with a trace of new snow. Winds have averaged 1-2 mph with gusts to 10 mph, west/southwest and south/southeast.
THIS SEASON PRECIPITATION for MT SHASTA CITY: Since October 1st (the wet season), we have received 21.16 inches of water, normal is 14.96 inches, putting us at 141% of normal. For the month of December we received 4.69 inches of water, normal is 7.60 inches, putting us at 62% of normal, and finally... for the year of 2016 we've received 54.06 inches of water, normal is 42.96 inches, putting us at 126% 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.
| 0600 temperature: | 24 |
| Max. temperature in the last 24 hours: | 43 |
| Average wind direction during the last 24 hours: | East/Northeast |
| Average wind speed during the last 24 hours: | 15-20 mi/hr |
| Maximum wind gust in the last 24 hours: | 10 mi/hr |
| New snowfall in the last 24 hours: | 40 inches |
| Total snow depth: | 40 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 | Sunny. | Mostly clear, then a 30% chance of snow showers after 4am. | Snow showers likely |
| Temperature (°F) | 34 | 16 | 19 |
| Wind (mi/hr) | Northeast 10-15 mph | North/Northeast 10-20 mph | West 15-20 mph |
| Precipitation SWE / Snowfall (in) | / 0 | / 0-.5 | / 2-4 |
| For 9000 ft to 11000 ft | |||
| Saturday | Saturday Night | Sunday | |
| Weather | Sunny and windy. | Windy. Mostly clear, then 30% chance snow showers. | Snow showers likely. Windy |
| Temperature (°F) | 27 | 3 | 3 |
| Wind (mi/hr) | East 30-40 mph | Northwest 0 | Northwest 50-60 mph |
| Precipitation SWE / Snowfall (in) | / 0 | / 0-.5 | / 1-3 |
