Mass Wasting, in it's many forms:

"Mass wasting" is a general term most people are unfamiliar with, but who's effects are very well known. Mass wasting is defined as "any type of downslope movement of earth materials." This can include land/rock slides, avalanche, or earth flows. Whatever the material involved, one constant in all of these events is a slope. Iceland is a very mountainous island. A large percentage of these slopes consist of loosely compacted volcanic materials. In addition, Iceland has significant snowfall in it's higher altitudes. These facts together mean that Iceland's most common forms of mass wasting are rock/land slides, and avalanches.

Landslide

Iceland suffers from landslides on a fairly regular basis. There was a significant slide into the caldera lake of the stratovolcano Askja in July of 2014, pictured here. 

While there was no loss of life, this slide was the largest recorded since the settlement of Iceland. Estimates place the volume of material displaced at 30-50 million cubic meters. Not all of this material went into the lake, but enough did to create a 20-30m (60-90ft) high tsunami all around the lake. Report on the Askja Landslide . It was very fortunate that this slide took place shortly before midnight, as people certainly would have been using the lake in daylight hours.


While a landslide may appear to humans to be a sudden, unpredictable event, this is not the case. Photographs from this and other slides show a gradual movement of large volumes of material over the course of years. This sudden movement was merely the culmination of many long years of instability. Any hillside should be treated as potentially hazardous, as all slopes are subject to the effects of gravity, and as such are always on their way down, to one extent or another.

Avalanche

 

As with any country with heavy snowfall and steep slopes, Iceland faces significant danger from Avalanche. Avalanche are caused by several factors in the snow. Sudden warming of snowpack on a slope can cause the upper levels to melt and saturate the lower layers with water, increasing the weight of the snow until it can no longer maintain it's position on the slope. Sudden rain onto existing snow will have the same effect. Wind blowing large quantities of snow onto the downwind side of a slope over a short time will also cause the mass of snow to become too great to maintain it's "angle of repose", the angle at which a mass can remain stationary on a slope. Avalanches are most common on slopes between 35 and 40 degrees. Grades below this lack the momentum necessary to create a dangerous flow, and grades above this tend to allow snow to constantly slide off. 

Read The Iceland Meteorological Office's section on avalanche here:

Danger Mitigation

Iceland recently commissioned a comprehensive study of all areas of avalanche risk. Iceland's Avalanche risk survey winds to a close. This initiative was started after two 1995 avalanches killed a total of 34 people in two towns in northern Iceland.  These tragic events highlighted both the underrated risk of avalanche in some areas of the country as well as the lack of preparedness for dealing with such events. After significantly increasing the collective knowledge of the Icelandic scientific community's understanding of avalanche risk and successfully developing a risk map and warning program for the island, the leftover funds from the assessment program are being redirected to increased mitigation of the effects of possible volcanic hazards.