NORTHERN CAIRNGORMS AVALANCHE HAZARD 1500 HRS THU 21/2/02 Even though the temperatures have remained well below freezing the new snow is very dense and forms a stiff slab. The prevailing wind has been Westerly with periodic variations to South-West and North-West. However the snow loading is extremely variable by elevation and aspect. Two slabs were triggered in Coire an t-Sneachda on an East aspect at about 900 metres. Where sampled at 1050 metres on a West aspect in Coire an Lochan there were faceted snow crystals forming under a crust that gave a very easy shear. The avalanche hazard is High (Category 4). AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Two avalanche cycles will occur in the next weather forecast period. The first caused by a rise in the freezing level to 1100 metres, followed by the second due to heavy snow and strong Westerly winds. The highly variable loading by elevation and aspect will continue. Even some West aspect terrain above 900 metres will have unstable snow. The approach slopes and exit ramps of many climbs will have significant load of unstable slab. The avalanche hazard will be High (Category 4). CLIMBING CONDITIONS SNOW DISTRIBUTION: Areas of deep new snow alternating with scoured areas. ICING: Limited observations reported due to weather. COMMENT: One of the few 'rules of thumb' in the avalanche game is "wait for the storm instability to pass". LOCHABER AVALANCHE HAZARD 1500 HRS THU 21/2/02 Snow has gradually turned to rain at all levels during Thursday morning. The snowpack has become increasing unstable during the day, with extensive wet snow instabilities developing. N, NE and E facing slopes and gullies are particularly affected. The avalanche hazard is High (Category 4). Cornices also unstable above these aspects. AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Colder temperatures are expected overnight accompanied by snow showers and strong Westerly winds. The existing wet snowpack will refreeze and become stable. Fresh deposits of unstable windslab will form in sheltered locations. Greatest accumulations will be on NE, E and SE facing slopes and gullies. Avalanches are likely in the above locations, especially later in the day. The avalanche hazard will be Considerable (Category 3). Cornices will reform and be unstable. CLIMBING CONDITIONS SNOW DISTRIBUTION: Extensive snow-ice forming on windward slopes on Friday. ICING: Freezing level lowering to 300m on Friday. COMMENT: Strong winds continuing. GLENCOE AVALANCHE HAZARD 1500 HRS THU 21/2/02 Cold conditions overnight followed by snow this morning with strong South-West winds added further layers to existing weakly bonded windslab. Accumulations are deepest on slopes with a North through to South-East aspect and in all gullies sheltered from the winds. Milder conditions with rain expected later in day will saturate the snowpack at all levels. The avalanche hazard is High (Category 4) where deep windslab exists, mainly above 850m. AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Freezing levels are expected to remain above the summits on Thursday night giving heavy rain or sleet at all levels. A period of high avalanche activity will occur during this period. Stability of the existing wet snowpack will improve as very cold conditions return on Friday morning. New snow by afternoon will fall at most levels. Gale force Westerly winds may give blizzard conditions for a time. Drifting snow will accumulate as weakly bonded windslab on slopes with a North-East to South-East aspect and in all sheltered gullies mainly above 850m. The avalanche hazard will rise to Considerable (Category 3) as new snow affects the area. Avalanches are likely CLIMBING CONDITIONS SNOW DISTRIBUTION: Above 400m on Thursday ICING: Above 700m becoming more extensive on Friday COMMENT: Climbing conditions improving on Friday. Extent will depend on how major Thursday night's thaw is. SOUTHERN CAIRNGORMS AVALANCHE HAZARD 1500 HRS THU 21/2/02 It has continued to snow throughout the day on variable winds. Weakly bonded windslab can be found in sheltered locations on NE through to S aspects above 800 metres. Deposits are deepest on E and SE aspects above 900 metres where stability remains very poor. The avalanche hazard is High (Category 4). AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Heavy rain is forecast for Thursday night with the freezing level at 1100 metres. This additional load will further destabilise the weakly bonded snowpack and avalanches will occur. Some consolidation will take place as temperatures lower on Friday but moderately to weakly bonded layers will still be found in deeper deposits. Fresh windslab will build in sheltered locations on NE to SE aspects. The avalanche hazard will be Considerable (Category 3). CLIMBING CONDITIONS SNOW DISTRIBUTION: Best above 900 metres. ICING:Rapid melt-freeze cycle forecast for next 24 hours. COMMENT: Careful route choice required at present. CREAG MEAGAIDH AVALANCHE HAZARD 1500 HRS THU 21/2/02 Variable gale to severe gale force winds have continued through the night with snow transportation forming weakly bonded windslab on many aspects. North through East to South-West aspects above 850 metres are particularly affected and loose snow avalanches were observed this morning from North and East aspects. The avalanche hazard is High (Category 4). AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Heavy sleet and snow overnight will continue to affect summits, by morning freezing levels will again drop and heavy snow on a storm force Westerly wind will continue. Deep unstable windslab will form on North through East to South aspects above 850 metres and fragile cornices will begin to build. The avalanche hazard will remain High (Category 4) and avalanches will occur. Triggering will be possible with low additional loads and run outs will be long. CLIMBING CONDITIONS SNOW DISTRIBUTION: Snow level rising in heavy rain. ICING: Thaw-freeze will help, but about to be buried again! COMMENT: ------------------------------------------------------------------------------- NORTHERN CAIRNGORMS AVALANCHE HAZARD 1500 HRS THU 21/2/02 Even though the temperatures have remained well below freezing the new snow is very dense and forms a stiff slab. The prevailing wind has been Westerly with periodic variations to South-West and North-West. However the snow loading is extremely variable by elevation and aspect. Two slabs were triggered in Coire an t-Sneachda on an East aspect at about 900 metres. Where sampled at 1050 metres on a West aspect in Coire an Lochan there were faceted snow crystals forming under a crust that gave a very easy shear. The avalanche hazard is High (Category 4). AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Two avalanche cycles will occur in the next weather forecast period. The first caused by a rise in the freezing level to 1100 metres, followed by the second due to heavy snow and strong Westerly winds. The highly variable loading by elevation and aspect will continue. Even some West aspect terrain above 900 metres will have unstable snow. The approach slopes and exit ramps of many climbs will have significant load of unstable slab. The avalanche hazard will be High (Category 4). CLIMBING CONDITIONS SNOW DISTRIBUTION: Areas of deep new snow alternating with scoured areas. ICING: Limited observations reported due to weather. COMMENT: One of the few 'rules of thumb' in the avalanche game is "wait for the storm instability to pass". LOCHABER AVALANCHE HAZARD 1500 HRS THU 21/2/02 Snow has gradually turned to rain at all levels during Thursday morning. The snowpack has become increasing unstable during the day, with extensive wet snow instabilities developing. N, NE and E facing slopes and gullies are particularly affected. The avalanche hazard is High (Category 4). Cornices also unstable above these aspects. AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Colder temperatures are expected overnight accompanied by snow showers and strong Westerly winds. The existing wet snowpack will refreeze and become stable. Fresh deposits of unstable windslab will form in sheltered locations. Greatest accumulations will be on NE, E and SE facing slopes and gullies. Avalanches are likely in the above locations, especially later in the day. The avalanche hazard will be Considerable (Category 3). Cornices will reform and be unstable. CLIMBING CONDITIONS SNOW DISTRIBUTION: Extensive snow-ice forming on windward slopes on Friday. ICING: Freezing level lowering to 300m on Friday. COMMENT: Strong winds continuing. GLENCOE AVALANCHE HAZARD 1500 HRS THU 21/2/02 Cold conditions overnight followed by snow this morning with strong South-West winds added further layers to existing weakly bonded windslab. Accumulations are deepest on slopes with a North through to South-East aspect and in all gullies sheltered from the winds. Milder conditions with rain expected later in day will saturate the snowpack at all levels. The avalanche hazard is High (Category 4) where deep windslab exists, mainly above 850m. AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Freezing levels are expected to remain above the summits on Thursday night giving heavy rain or sleet at all levels. A period of high avalanche activity will occur during this period. Stability of the existing wet snowpack will improve as very cold conditions return on Friday morning. New snow by afternoon will fall at most levels. Gale force Westerly winds may give blizzard conditions for a time. Drifting snow will accumulate as weakly bonded windslab on slopes with a North-East to South-East aspect and in all sheltered gullies mainly above 850m. The avalanche hazard will rise to Considerable (Category 3) as new snow affects the area. Avalanches are likely CLIMBING CONDITIONS SNOW DISTRIBUTION: Above 400m on Thursday ICING: Above 700m becoming more extensive on Friday COMMENT: Climbing conditions improving on Friday. Extent will depend on how major Thursday night's thaw is. SOUTHERN CAIRNGORMS AVALANCHE HAZARD 1500 HRS THU 21/2/02 It has continued to snow throughout the day on variable winds. Weakly bonded windslab can be found in sheltered locations on NE through to S aspects above 800 metres. Deposits are deepest on E and SE aspects above 900 metres where stability remains very poor. The avalanche hazard is High (Category 4). AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Heavy rain is forecast for Thursday night with the freezing level at 1100 metres. This additional load will further destabilise the weakly bonded snowpack and avalanches will occur. Some consolidation will take place as temperatures lower on Friday but moderately to weakly bonded layers will still be found in deeper deposits. Fresh windslab will build in sheltered locations on NE to SE aspects. The avalanche hazard will be Considerable (Category 3). CLIMBING CONDITIONS SNOW DISTRIBUTION: Best above 900 metres. ICING:Rapid melt-freeze cycle forecast for next 24 hours. COMMENT: Careful route choice required at present. CREAG MEAGAIDH AVALANCHE HAZARD 1500 HRS THU 21/2/02 Variable gale to severe gale force winds have continued through the night with snow transportation forming weakly bonded windslab on many aspects. North through East to South-West aspects above 850 metres are particularly affected and loose snow avalanches were observed this morning from North and East aspects. The avalanche hazard is High (Category 4). AVALANCHE HAZARD OUTLOOK FRI 22/2/02 Heavy sleet and snow overnight will continue to affect summits, by morning freezing levels will again drop and heavy snow on a storm force Westerly wind will continue. Deep unstable windslab will form on North through East to South aspects above 850 metres and fragile cornices will begin to build. The avalanche hazard will remain High (Category 4) and avalanches will occur. Triggering will be possible with low additional loads and run outs will be long. CLIMBING CONDITIONS SNOW DISTRIBUTION: Snow level rising in heavy rain. ICING: Thaw-freeze will help, but about to be buried again! COMMENT: -------------------------------------------------------------------------------