Avalanche Report for Glencoe
Avalanche Hazard Forecast
FOR PERIOD 18:00 Thu 26/02/2015 TO 18:00 Fri 27/02/2015
Forcasted Snow Stability & Avalanche Hazard
Fresh unstable windslab will form on North to East aspects with sheltered areas in North-West and South-East aspects affected by cross loading. These deposits will lie mainly above 700 metres. Areas exposed to the wind will be generally stable with a firm crust. The avalanche hazard will be Considerable.
Forcasted Weather Influences
The wind will be gale force West-South-West backing South-South-West and easing. There will be steady snow showers above 400 metres throughout the period. The freezing level will be around 400 metres.
Key Snow Stability Observations
Observed Avalanche Hazard -
Observed Weather Influences
The wind was strong from a West-South-West direction. There were steady snow showers above 300 metres through the morning. The freezing level was around 400 metres.
Observed Snow Stability and Avalanche Hazard
Generally the snowpack has gone through a thaw/refreeze cycle and is more stable. Evidence of a number of wet slab releases overnight was observed on North to East aspects above 700 metres. Some fresh unstable windslab has formed above 700 metres on North-East to East aspects with North and South-East aspects affected by cross loading. The avalanche hazard is Moderate.
Diminishing snowpack, good above 700 metres on North to South-East aspects. Good visibility initially - becoming more restricted by mid-day. Winds 20 -30 mph progress difficult at times with stronger gusts.
Evidence of a number of overnight wet slab releases was observed - notably on the Glen Etive flank of Buachaille Etive Mor and below Great Gully on the same hill.
The period has seen the progressive build up over six days of windslab accumulations on North-West through North-East to South-East aspects. There was evidence during this time of natural slab avalanches on Easterly aspects above 900 metres. This was followed by an abrupt overnight thaw after which debris from a number of wet slab releases was observed. The period ended with a return to cold weather, which has refrozen the snowpack, and the accumulation of some fresh windslab deposits.
The period began with a continuation of the relatively settled weather - generally dry with the snowpack gradually consolidating and becoming more stable. The second half of the period was characterised by more unsettled weather with considerable accumulations of fresh unstable windslab forming. This was followed by thaw conditions which moistened and softened the snowpack occasioning some cornice collapse but no major slab releases. Falling temperatures are now stabilising the snowpack.
12/02/2015 The week has been dry apart from the odd snow flurry and some drizzle. Freezing levels have been complex with temperature inversions for much of the time where general freezing levels were above the summits with a fluctuating sub zero band lying below. This has given some great atmospheric hill days where visibility existed mainly on the hills at the Eastern end of the glen. The snowpack today is firm and icy. There not been a significant reduction in snow cover throughout the period.
The period has been characterised by Northerly winds and low temperatures, with the freezing level mainly between 200 - 300 metres. This has resulted in windslab accumulations mainly on North-East through South to South-West aspects and other slopes being mainly scoured and stable. There was some redistribution of the snowpack by changes in the wind direction but accumulations were generally light. The period has ended with a rise in the temperature which will start to consolidate the snowpack.
Fluctuating conditions with three significant thaw periods have caused the snowpack to go through a series of melt/freeze cycles resulting in a diminished and stable snowpack towards the end of the period. Further snowfall at all levels has produced fresh windslab on this firm base.
The area had significant snow fall at the early part of this period, the Avalanche hazard then increase to High. The snowpack settled slightly but areas of weakly bonded windslab remained on North to South-East aspects. Colder, clear conditions with light winds then prevailed, during the last 3 days, winds have shifted to South-Easterly but it has remained dry, some light redistribution has taken place. The avalanche hazard has been Considerable from the 16th January to date.
The period started with a thaw which diminished the snow pack and produced wet snow instabilities. The subsequent fall in temperature consolidated the snowpack and this thaw/ freeze cycle was repeated. It then became considerably colder and the end of the period has been characterised by heavier snowfall accompanied by hail which has lead to widespread unstable conditions higher up, and snow at road level.
The weather during the last seven days has been dominated by a couple of large thaws with cooler but drier periods in-between. The snowpack is not extensive,with the main accumulations being on North to East aspects above 800 metres. The amounts of snow which has arrived between the thaws has been been quite small, and these deposits have tended to consolidate quite rapidly in variable weather. No avalanches were recorded in the area during the week.
The period started with cold conditions with some fresh snow and wind redistribution of the snowpack creating windslab on mainly Eastern aspects. As the temperature started to rise and it became increasingly rainy, wet snow instabilities were produced in the existing deposits of windslab as the snowpack became increasingly moist and soft. The temperature at the end of the period is starting to fall and the snowpack will be consolidating.
After some fresh snow last Friday and Saturday, there was a major thaw on Sunday. Heavy rain and summit temperature of plus five degrees had a significant affect on the snowpack. From Monday it slowly turned colder, the existing snowpack froze, and there were further windslab deposits. The majority of the snowpack lies on North through East to South-East aspects above 700metres. The avalanche hazard category was considerable for most of the time. No avalanches were recorded during the period.
The first week of the season has been mostly been cold with snow showers. There was a brief thaw on Saturday night and then a more significant one through Wednesday and Thursday. Winds have been consistantly from between the South-West and North-West, and so windward aspects hold little snow, particularly after the thaw. Significant deposits, which have now generally stabilised, exist on lee ascents. A couple of relatively small avalanches were reported, one triggered and the other natural.
The snowpack has been mainly isothermic and moist at most levels for the past week and is generally well bonded and stable. We have encountered South, South-West and Westesterly weather influences with the freezing level generally above the summits. The avalanche hazard has been Low for 6 of the days with one day with a localised Moderate hazard. The day Moderate (localised) was forecast did not materialize because new snow amounts were not significant. This is the last summary of the 2013/2014
The snowpack has been isothermic and moist at most levels for the past week and is generally well bonded and stable. We have encountered Easterly weather influences with the freezing level generally above the summits. The avalanche hazard has been Low for 6 of the days with one day with a localised Moderate hazard.
Wintery conditions returned last Friday 21 March with a fair amount of new snow over the next two days mainly above 800 metres. Victim triggered avalanches were recorded on Sunday. Windy conditions followed with strong to gale South-Easterlies affecting the area. Natural avalanches were recorded on East and North West slopes. On Tuesday a return to milder conditions saw rain affecting all levels. Wednesday was dry and mild and Thursday colder with snow showers and Easterly winds.
Its been a stormy week with unsettled mild weather on most days. Rain has fallen at all levels until today when snow fell above 700m. During the week the snowpack has been moist with wet snow instabilities on steep slopes, no avalanche have been recorded. At present, the new accumulations of snow and windslab are not to depth and mostly on North to East aspect and give a localised Considereable hazard. More snow is forecast for the next few days with the freezing level around 600-800 metres.
The period started with mild weather leading to wet snow instabilities. As temperatures fell stability of the snowpack generally improved. Levels of precipitation were low and there was some fine sunny weather which produced some instabilities on South facing slopes. The temperature rising with some rain increased the avalanche risk at the end of the period. Cornice collapse remained a serious issue throughout the period.
The week has been challenging for snowpack stability there have been many avalanches this week at least 12 recorded. The avalanche category was generally Considerable with avalanches are likely and the last 2 days have had a High category and again avalanches did happen. The snow was generally dry for the first part of the week but now it is moist especially at lower levels.
Another stormy week with a fair amount of new snow on the higher slopes on most days apart from 23rd which was wet at all levels. Snow quantities in the Glencoe area remain exceptionally high on the upper slopes. Winds have mainly been from a South-East through South to Westerly direction.
The stormy conditions have continued. Winds have been strong with snowfall occurring most days which has continued to build up large areas of windslab and bury huts and lifts in the ski area. There has been some avalanche activity recorded, most notably a large natural avalanche out of Great Gully on Buachaille Etive Mor on Sunday night. It is likely there has been a lot of avalanches which have not been recorded due to the poor visibility.
There has been extensive and deep snow cover above 600m all week. Strong SE winds during the first part of this period continued to deposit unstable windslab on SW through W and N to NE aspects mainly above 700m, with natural and triggered avalanches recorded on Thursday and Sunday. From Sunday onwards mainly strong winds varied between SE and SW depositing windslab mainly on W through N to E aspects above 750m.
There is an extensive and very deep cover of snow above 700 metres with strangely very little, if any accumulations in the glens. Over the last week winds have been predominantly from the South, then South East, very strong at times. This has lead to a significant build up of windslab in many sheltered gullies and South West through North to North East aspects. With continuing colder temperatures, many of these areas remain unstable.
Temperature fluctuations at the start of this period consolidated the existing snowpack. Fresh windslab was then deposited mainly on W to N to NE aspects above 800m, with winds that varied between SE and SW. Over Wednesday night and during Thursday there was significant snowfall with strong SSW to WNW winds which deposited deep accumulations of fresh unstable windslab, mainly on NW through N and E to SE aspects above 750m.
At first winds were mainly South-Westerly and windslab formed primarily on North to East aspects above 800m. Then from Sunday winds became Southerly or South-Easterly and windslab was present on West through North to East aspects above 800m. During Wednesday the freezing level rose above the summits and in the late afternoon and early evening heavy rain fell at all levels. On Thursday the freezing level dropped to around 900m and the snowpack started to refreeze and consolidate.
Above 800 metres there is an extensive cover of snow on North-Westerly through North to South-Easterly aspects. A recent melt -freeze cycle has rendered much of the older snowpack firm and stable. Some areas of fresh windslab are forming in sheltered locations such as gully exits and steep Northerly and Easterly aspects. Below 700 metres the snow cover is much depleted due to milder conditions and rain.
Significant accumulations of snow are still present on most aspects especially above 650 metres. The snowpack stability has varied during the past 7 days it started off being very unstable and has now become almost isothermic. Changeable unsettled weather is forecast for the next few days with more snowfall which will produce more instabilities. The greatest accumulations are mainly on W to N to SE aspects above 750m.
Stormy conditions over the last few days added a deep cover of snow on North-West through North to Easterly aspects initially down to lower levels. Many windward slopes are fairly clear of any significant cover. Outlook is milder on Friday then frequent snow showers on Saturday.
Significant accumulations of snow compared to last week. Winter snowpack developing on mainly NW to N to SE aspects above 750m. Immediate concerns (Thursday 19 Dec) are rising temperatures in the forecast period combined with new snow instability on above noted aspects and elevations.
Limited snowpack with patches mainly on North through East to South-East aspects above 850m.