Avalanche Information, Mountain Danger and Risk

Where do avalanches tend to occur in the Sierra Nevada?

As an aid to climbers, mountaineers, ski tourers and walkers for each winter season, each winter we post Avalanche Information and Risk Assessments on our Weather Page based on the highly successful Scottish service that has been in use for many years.

As we are in the hills most days during the winter and are consistently in a position to evaluate the danger, this safety information will be made available to all interested parties through our websites and blogs. This service is in operation from mid-December each year and will be updated as and when conditions materially change.


Most winters after fresh snowfall there are avalanches all over the Sierras, but they are normally small and localised. The exception was in February 2011 when a massive slide nearly 1km wide in the Barranco de San Juan killed 1 person and injured 2 others.

Click map below for enlarged, clearer version

ski touring avalanche risks

There are 4 major black spots that regularly avalanche. They have become black spots because they cross normal walking or hiking trails that people use. They are:

Of course, normal good mountaineering and avalanche awareness practices must be observed on all routes in the high mountains, but the above black spots can and should always be avoided or by-passed.

avalance risks in the sierra nevada mountains


After a southerly front from the African continent passes northwards through the Sierra Nevada there is a rapid rise in temperatures followed by the quick return to the norm of below zero. This leaves the Sierra Nevada like a gigantic “block of ice” where a slip from a tired or inexperienced mountaineer can have disastrous consequences.

In winter 2014 many experienced mountaineers got into difficulties on simple routes and had to ask for assistance from the rescue services. Forget about ski touring in these conditions and stick to the pistes!


Predominantly from the west they are a constant companion in the high mountains. It is not uncommon for gusts of over 120km/hr to be recorded every winter, indeed an exceptional winter gust of over 250 Km/hr was once recorded at an altitude of 2800m.

Progress will be difficult and may well be impossible in winds over 60km/hr, especially or ridge crests and in areas where the wind is funneled through passes such as the Collado de Carihuela. When strong, bitterly cold winds arrive from the north then the windchill will be extremely high.


Needless to say a combination of snow and high winds can make these relatively gentle and easily accessible mountains into a life and death struggle. It is important to remember and respect the high altitudes and sometimes long distances involved to safety.

Local mountaineers don’t leave home in these conditions, but if you do happen to get caught out then it is important to have done your homework before setting out regarding map, compass, escape routes etc. With today’s wealth of internet weather resources available then this should not occur.

Snow Bridge Collapse

This occurs in the spring melt when rivers and streams carve tunnels beneath the valley snows. The unstable snows above look perfectly fine to walk on but can collapse causing injury.

Electrical Storms

These are common occurrences in the late spring and autumn but are rare in winter. Usually sufficient warning of these risks will be posted on the AEMET website

ski touring avalanche risks

Avalanche Hazard Scale

Degree of hazard - 1 LOW

Degree of hazard - 2 MODERATE

Degree of hazard - 3 CONSIDERABLE

Degree of hazard - 4 HIGH

Degree of hazard - 5 VERY HIGH


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