The description of the video on youtube is amusing:
A helicopter smacks down a rock off a cliff face to eliminate a rock fall hazard for the road below. The helicopter than displays it's dominance of the Fjord by urinating all over the rock face. This is done to loosen and remove any remaining small rocks that may fail at another time and cream a volvo or saab on the road below.
By Stich From Colorado Springs, Colorado Dec 23, 2009
Speaking of artillery...
Sadly, we used to have a lot of surplus howitzer artillery from WWII that was put to good use in avalanche mitigation. Recoiless rifles were also used, but one exploded in the tube and killed the operator once and they fell out of favor. Artillery is not cheap anymore, as it is much more complex and consequently more expensive. So they use air cannons now amongst other methods.