Avalanche Advisory Archive Pre-2016
Date Issued: | 2013-12-30 |
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Danger: | 3 |
Trend: | 4 |
Probability: | 0 |
Size: | 2 |
Problem: | 0 |
Discussion: | The National Weather Service Forecasts- TODAY...SNOW...MIXED WITH RAIN AT TIMES IN THE AFTERNOON. SNOW TONIGHT...RAIN AND SNOW. SNOW ACCUMULATION TO 4 INCHES. LOWS 29 TO 35. SOUTHEAST WIND 5 TO 15 MPH. TUESDAY...RAIN AND SNOW SHOWERS LIKELY. SNOW ACCUMULATION TO 2 Temperatures cooled off 1c degree over the last 24 hours. This is keeping it below freezing nearly to sea level placing all the precip in our starting zones as new snow over the last few days. We have only seen about 5mm of precipitation at the Mt Roberts Tram Summit since 1am last night. This has left about 5-6cm of new snow. Accumulation rates appear to be picking up at present. Snowfall rates nearing one inch per hour are expected. This will raise the avalanche danger rapidly. Winds have been from 10-25mph as this new snow settled in. Look to see additional danger in windloaded faces. Our prominent winds have been from the South to the East meaning we will want to use extra caution on N-W Faces. The new snow from two days ago was bonding fairly well. There were isolated areas of weakness also in windloaded pockets from that event. Thus far we have not seen large volumes of new snow for either the 12 hour period or the 48 hour period... but conditions are changing rapidly currently. I will be placing the danger scale at Considerable today due to new snow, winds, snowfall rates, minor cooling, and more snow to come. Natural avalanches are possible today in windloaded pockets. Human triggered avalanches are more likely today to to adding the extra trigger (YOU)> Please use extreme caution in the mountains today. Please avoid the Flume and Perseverance Trail. Please do not hike in the gated areas above the Berhands Neighborhood. Please also do not walk through or park in the avalanche zones along thane road. Slide sizes are not predicted to be large enough to affect the urban areas yet recognize it doesn't take much of a slide to bury a person. Remember this is an URBAN forecast and not a backcountry one. Be sure to make good assessments and decisions independently of any forecast. |
Tip: | Dig quick pits on your ascent. A hasty pit is a hole dug in the snow that helps you identify weak and strong layers. If you suspect that there may be a weak layer buried deeply, you should always dig below that point. Otherwise a hole about one meter (3 ft) deep should be sufficient. Once you dig the hole, you will be able to see major layers on the wall of the snow pit. You can detect hard strong layers and soft weak layers by poking the exposed layers in the wall of the pit with your finger, or by brushing the pit wall with your hand and looking for hard and less hard layers. You can also slide a credit card or ruler down through the layers and note the changes in resistance. An additional indicator that will help you identify layers that otherwise may be hard to detect is the shovel shear. The more observations you make and stability tests you perform the more apt you are to accurately assess the stability. Relying on one piece of data is like getting married on your first date. Sometimes it works, but generally it's not a good idea. Where should I dig a pit? It can be difficult to choose a place to dig a pit. Choose a representative spot and a safe spot that has undisturbed snow conditions similar to the slope you want to ride. In other words, you don't want to dig in an area that is wind scoured, has a big cornice, machine tracks, or bunches of vegetation. Dig on a slope small enough that even if it slides you will not get hurt or. Do I need to dig on a steep slope? No. Always start by digging on a slope less than 30 degrees before entering steeper terrain. Also recent research has shown that you can conduct stability tests on slopes less than 30 degrees and find similar results as you would on steeper slopes...as long as the snowpack structure is reasonably consistent. Ask yourself these questions: ?Is it safe? If the Terrain is Steep When you're gathering data on slopes steeper than the low 30? range, consider using a belay. If your plans include exploring steep terrain, a small climbing rope should always be included in your gear. Lower your partner onto a portion of the slope that has undisturbed snow conditions representative of the overall slope. Do not dig your pit beneath a cornice. |