Avalanche Advisory Archive 2016 – 2018
Date Issued: | 2017-01-10 06:14:43 |
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Danger: | 2 |
Primary Trend: | 2 |
Primary Probability: | 3 |
Primary Likelihood: | 1 |
Primary Size: | 1 |
Primary Description: | These Taku wind events directly load our urban enviroment in places. Be aware that danger is increased in windloaded areas. Be aware that with winds this high snow can deposit in unusual places. If you find new snow deposits from windloading be aware these are areas of increased concern. It will take a while for this weakness to go away... be cautious in windloaded areas. |
Secondary Trend: | 2 |
Secondary Probability: | 5 |
Secondary Likelihood: | 1 |
Secondary Size: | 2 |
Secondary Description: | As we see increased windloading one of the concerns is we place enough mass on these deep hard slabs to actually get the slab to a state of instability. This could be 3-6' deep in places. The odds of triggering this layer are not good and yet should it be triggered these will be VERY LARGE avalanches... Reduce your esposure to large avalanche paths and avoid spending time in them. Once again although not likely to be triggered these slides on the deeper weak layer in place are possible. Especially in our urban enviroment along the channel. Look at the ground snow interface to see if you have facets in the areas you recreate. If you are seeing large facets and depth hoar recognize this is a dangerous condition. |
Discussion: | The National Weather Service Forecasts- Today- Mostly sunny. Highs 18 to 30. Warmest near downtown juneau and douglas. Light winds. Tonight- Mostly clear. Lows 15 to 20. Light winds. Wednesday- Increasing clouds. Chance of snow in the afternoon. Highs around 28. North wind 10 mph. Temperatures this morning remain cool although several degrees warmer than yesterday. Yesterday morning temperatures were around 16 degrees at Eaglecrest and Mt Roberts Tram Summits. This morning they are closer to 25f degrees. These warmer temps will help the snow over time to settle bond, and heal. We have not seen any precipitation in about 10 days. Winds have been blistering for the last 3-4 days. We have seen tremendous wind transport around the region. Dangers are not widespread... but danger is present in windloaded areas... wherever they may be... Be aware if you are on snow that is recently deposited from the wind event it may be a weak windslab. Avalanche Danger remains MODERATE around the region. Natural and human triggered avalanches are not likely yet still possible in isolated areas. |
Tip: | Avalanche Safety in the Backcountry A reminder: avalanche danger is greatest during and shortly after intensive snow falls. Traveling on or below 30 degree slopes during intensive storms is very dangerous. (Intensive storms are those in which 1\" of snow falls per hour) Watch for the leeward pockets.? In much of interior west, many of the mid and low elevation slopes have a lot of sagebrush showing, but every so often there are pockets?sides of gullies, steep short slopes and back sides of ridges?where the wind has deposited snow.? Plan your route to avoid these areas.? In the Pocatello, Idaho area alone, 6 deaths can be attributed to people being caught in short avalanches that occurred in leeward pockets. One extremely dangerous time in the mountains occurs when a period of cold weather is followed by a sudden warming trend or rain falling on the snow pack.? Free water in the snow pack lubricates weak layers and often large avalanches result.? Like intensive storms, it is a very dangerous time to be traveling in the mountains. Heavy trees provide protection from avalanches, but the trees must be spaced within 3 meters of one another.? That's close enough to make skiing annoying.? Sparse trees do NOT provide any more protection than open slopes. In the spring, big wet, damaging avalanches can occur.? The safest time to travel is in the morning after a cold, clear night when the snow is frozen.? Get off of steep slopes when the snow begins to soften from melting. When crossing suspected avalanche slopes, do so one person at a time. Travel from island of safety (a group of heavy trees, a ridge top, etc) to island of safety. Don't camp, eat lunch and rest below obvious avalanche paths. Carry emergency avalanche equipment:? transceiver, portable shovels, probe poles, compass with inclinometer, and hand lens.? At the beginning of each winter season practice with your transceiver.? Know how to use it before you need to use it. If you are moving up or down a suspected slope, stay to the side.? If an avalanche occurs, the snow may move slower on the flank and allow escape. Stay out of gullies.? They are natural pathways for avalanches and often fill deeply with snow when an avalanche occurs. Know what's out there.? Check the avalanche forecast before leaving on a backcountry trip. |
Forecaster: | Tom Mattice |