How Flooding in the Canadian Rockies Occurs

Friday, July 5, 2013

How Flooding in the Canadian Rockies Occurs

Warm weather, snow in the mountains, and a large amount of rainfall might be the recipe for a major flood.  Calgary experienced a major flood in June of 2013 and these above mentioned factors were the significant factors on why flooding occurs in the Canadian Rockies.  

Sometimes, in the Rockies, weather patterns and systems work in ways that can cause a greater flood damage potential.  Along with the heavy rainfall in June, there were unexpected weather changes and changes in the wind patterns.   A high pressure system was created towards the northern region and the winds were blowing towards the west, which in fact, was the opposite direction of the prevailing winds through Canada. This high pressure system prevented the storm from moving north.   The Rockies then in turn prevented it from moving west. Hence, the rainfall seemed to hover over the exact same area for hours on end.  With the amount of snow that was still in the mountains, the rainfall, and in some areas, saturated ground would not absorb any more water.  

Before this flood situation, the average rainfall was approximately 40 millimeters.  However, in June, over 200 millimeters of rainfall fell in some places in the Canadian Rockies and it created havoc.

In June, of 2013, storm sewers and drains backed up, water started moving overland, eroding new channels and erupting already full rivers.   All in all, thousands of people were evacuated from their homes, homes were lost, and the damage is estimated to be in the millions.

Is it possible for meteorologists to predict such an event?  Models have been created to develop statistics, but one never truly knows how devastating Mother Nature can be.  In this case, no one was able to foresee and predict just how deadly this flood would be, and how many damaging effects it had.