Avalanche Advisory Archive Pre-2016
| Date Issued: | 2012-02-02 |
|---|---|
| Danger: | 4 |
| Trend: | 3 |
| Probability: | 5 |
| Size: | 3 |
| Problem: | 0 |
| Discussion: | The National Weather Service Forecasts- TODAY...RAIN. HIGHS AROUND 41...TEMPERATURES FALLING IN THE TONIGHT...RAIN...HEAVY AT TIMES. BECOMING VERY WINDY. LOWS AROUND 34 RISING TO NEAR 40 LATE. NORTHEAST WIND 10 MPH BECOMING SOUTHEAST 25 TO 35 MPH WITH GUSTS TO AROUND 55 MPH LATE. FRIDAY...VERY WINDY. RAIN. HIGHS AROUND 44. SOUTHEAST WIND Thane Road slid and buried the road just after midnight last night. DOT Crews will be playing cleanup this morning. My understanding is they like to do avalanche control once again before placing crews in the slide path. I do not forsee the road being open before noon but this is a DOT question... Just wanted everyone to know AVALANCHES ARE STILL OCCURING. From 4pm yesterday until Midnight we had just barely negative temperatures, 30-60mph winds, 18mm of precip at the Tram Summit Weather Station, and about 13cm of new snow. You can expect there to be more snow at higher elevations adding to the stress and mass equasions. From after midnight until 6:30am temperatures rose from 31f to 34f at the tram summit. Winds have slowed to 20-40MPH out of the SSE. We expect to see slightly cooling temperatures through this morning with only .21\" of precip through the 3pm hour. After 3pm today through 3 pm tomorrow we expect to see temperatures rising by 5degrees to the warmest temperatures we have seen in well over a month, maybe more. During this time we expect large amounts of rain coming out of this tropical fetch. From 3pm to 3am tonight expect as much as an additional 1.05\" of precip, then from 3am Friday until 3pm Friday we expect as much as another .8\". Bringing our 24 hour totals to 1.85\" which will place tremendous stress on the snowpack especially at the warmest temps we have seen in quite some time. With the warmest temps we have seen in months, and the largest volumes of moisture we have seen all season... Avalanche Danger will remain HIGH. Lower weak layers in the snowpack that were previously dormant will become suspect once again. So even though we have now had several avalanches in some of our larger urban avalanche paths that is not to say we couldnt see another round of slides at perhaps even greater sizes?? STAY OUT OF AVALANCHE PRONE AREAS FOR THE NEXT 36-48 HOURS! Here is a little more back data for you that I wrote last night around 8pm. From midnight on the 30th until 2pm on the 1st we received approx 20mm(.8) of new snow. This could have been nearly 8\" of new snow at our local summit elevations. During that time we had considerable winds out of the SSE. We had several weak layers in place previous to this event and had been slowly building towards a natural avalanche cycle by placing this very heavy snow on the previous soft snows in place. Mid-day on the 1st from 2-4:30 we had a breif spike in temperatures from 31-33.5F at Tram Summit elevations. During that time we had 6mm of precip and roughly 6cm of new snow with 40-60mph winds out of the SSE. The combination of these events was enough to lead us into a direct action avalanche cycle. The snowpack had reached maximum load capacity and the direct affect of the new snow, warming, and wind kicked off a natural avalanche cycle. Avalanches were sighted on multiple aspects throughout the Juneau region. In this period of 2+ hours I received calls about a number of natural avalanches. The Bathe Creek Avalanche path was reported to have slid. Several other paths were also reported to have slid on several aspects of Mt Roberts. Towards the end of this event the Berhands path slid. Although this avalanche probably started as a dry slab avalanche near the summit elevations it quickly turned into a wet avalanche at lower elevations. This slowed the slide considerably and it then started to follow the terrain. The transverse gulley at the bottom of the avalanche path which had a fair amount of snow in it still caught most of the slide and directed it towards the south. This natural avalanche stopped below Judy Avenue and above Troy Avenue. It stayed North of the closed road gates and did not affect the urban residents in the avalanche path. As it was near dark I was not able to see how much of the starting zone released. If not all of the starting zone released there is still natural avalanche potential in this path. Please do not go up into the area to look or to walk your dogs above the close road gates. It is still questionably unsafe in that area. There are still several other avalanche paths in the urban enviroment that have not slid and the potential remains. Avalanche danger is HIGH at this time and will remain HIGH for the next 48 hours. Even though some paths have shed. They will continue loading overnight. And with multiple weak layers in place there is potential for avalanches to release at deeper depths than we have seen previously. Size during this type of an event is hard to predict but it is fair to say they will not be small... Danger will remain high and avalanche sizes will vary from path to path. Do your best to avoid travel in avalanche prone areas for the next 48 hours. Limit your time along places such as Thane Road, The Flume and Perseverance Trail. Recognize the White Path has not slid yet nor have the other urban paths from the Berhands Path all the way over to the White Path just North of Wickersham Ave. Backcountry danger is also quite HIGH! I dont think you would find me skiing in the backcountry today folks... Take a day to hide away... and live to ski another day... Potentially destructive natural avalanches likely to come near or reach developed areas, natural and human triggered avalanches likely. |
| Tip: | Here is a link to the Urban Avalanche Zone Maps- Please take a look and do your best to avoid travel in these places. http://www.juneau.org/avalanche/images/DowntownJuneauMapBIGWEB.jpg |
