Front Range =========== Current Keywords: CONSIDERABLE, LOW, MODERATE, avalanche danger, cross loading, depth hoar, drifts, faceted, faceting, high pressure, human triggered, human triggered avalanches, orographic, slab, weak layers, wind loading, wind slabs, windloading, windslabs, Mountain Weather and Avalanche Forecast for the Front Range Zone Forecast Issued on 12/30/2007 6:23:32 AM Forecaster: Ann Mellick Weather Synopsis Unsettled weather continues with more snow and gusty winds statewide. The upper level jet core noses over the state this afternoon producing pummeling winds in the high country. Expect waves of snow today, favoring the Northern Mountains, particularly the Steamboat area. Snowfall will be strongest this afternoon into this evening with increasing cold air advection and northwest orographic support. Moisture and strong northwesterly winds decrease Monday afternoon as a ridge of high pressure builds into the area. Temperatures will be very cold Monday night as skies clear. Dry and milder conditions will prevail Tuesday through late in the week. Weather Sunday Sunday Night Monday Temperature(°F) 5-10 -2 to 3 0-5 Wind Speed(mph) 25-35 G/70 25-35 G/70 20-30 G/50 Wind Direction W WNW WNW Sky Cover Overcast Overcast Mostly Cloudy Snow(in) 3-6 2-5 1-3 Snowpack Discussion Only 1 inch of new snow fell in the last 24 hours, though fierce winds have been blasting the peaks and redistributing existing snow. Winter Park reported a peak gust of 101 mph over night! Fresh windslabs will become an increasing problem for the remainder of the weekend and into next week. The last avalanche reported in the Front Range occurred Friday afternoon when a skier triggered an avalanche in Nitro Chute, just northwest of Berthoud Pass. It is a steep northeast aspect near treeline, and the avalanche broke to the ground, about 2 feet deep and 50 feet wide. The avalanche failed in depth hoar, and was probably triggered from a shallow area that has faceted and lost strength in the recent cold temperatures. In the Vail Summit zone, skiers have triggered a couple other slides, and found increasingly sensitive windslabs. Strong winds out of the southwest, west, and northwest have created and will continue to create fresh drifts and windslabs near and above treeline. You will find a variety of conditions, from soft to hard windslabs, especially on steep easterly aspects. The slabs will be getting deeper and more extensive as snow and strong winds continue. Areas of wind loading and cross loading can now be found on slopes facing north through east through south. Observers report extremely variable conditions above treeline with some spots scoured down to the tundra and adjacent spots loaded with thick wind slabs. These slabs will be getting deeper and more as bits of snow and very strong winds continue. The cold temperatures have really put the faceting process into overdrive - a process that is progressively weakening the snowpack. Fragile depth hoar continues to grow near the ground, and the upper layers of the snowpack are faceting and loosing strength too. The layers become weaker as the grains grow larger. The potential for full depth avalanches is slowly increasing. The most suspect slopes continue to be north through east where the snowpack is most complicated with a combination of new snow, new and old wind slabs, and a weak, faceted base layer. Human triggered slides remain probable on north through east aspects with windloading. So the picture is growing windslabs sitting on weakening snow sitting above a growing deep slab instability issue. If you dig below the surface it will resemble a sugar factory. Multiple weak layers in the snowpack and a high degree of variability from one slope to the next require a cautious approach to backcountry travel. Get out there, but as always use good route finding skills and smart backcountry protocols. Avalanche Danger The avalanche danger is CONSIDERABLE on north, northeast, east, and southeast aspects near and above treeline. Human triggered avalanches are probable on steep slopes with windslabs, drifts, or pillows. Winds have worked the snowpack over, leaving plenty of scoured, bare ground adjacent to the heavily loaded slopes. On northwest, west, southwest, and south aspects near and above treeline the danger is MODERATE. Below treeline the danger is MODERATE on north, northeast, east, and southeast aspects and LOW on other aspects.