Flooding Threat from Massive Snowpack

During the winter season of 2013-2014 there have been many more avalanches than in previous years. The season has been the harshest in decades — in some localities, the harshest in centuries. In certain areas, snowfall has broken ALL records since recording began over a 100 years ago.

It seems that every day brings another story of snowmobilers, skiers, or hikers being swept away by an avalanche. In late February of 2014, an avalanche roared into a residential area of Missoula, Montana, leveling a home and burying three people. Fortunately, the three victims were uncovered by rescuers and transported to a hospital.

Meanwhile, in California, months of extreme record-breaking drought were interrupted by furious storms that will not break the drought, but have produced dangerous mudslides and widespread flooding. When parched, cracked ground is deluged suddenly, little of the water is able to penetrate the hard-packed earth, and the vast majority of the water runs off; often in exactly the wrong direction.

Conversely, in most of the continental US, this winter has brought too much precipitation. Areas that have been persistently inundated this winter now have ground that cannot absorb any more water. And yet, many of these areas have an immense snowpack that will inevitably melt, resulting in far too much water — all at once — for the sodden ground to soak up.

Record snowfall, particularly in the western states, has produced a mountainous snowpack that exceeds a depth of 23′ in some places. The impact of this much snow, melting all at once, cannot be taken lightly. There is simply no place for all that water. Should a sudden thaw take place, disaster experts predict flooding of biblical proportions.

Rivers that are already at the bursting point will be presented with massive amounts of runoff from snowpack melt. Add to that the normal spring showers that happen every year, and these rivers will surely breach banks, levees, and flood walls this spring. Authorities from Montana to Maryland are anxiously eyeing weather reports and stepping up flood defenses.

Floods kill more people than hurricanes, lightning, or tornados in a given year, and this spring thaw could bring deadly results in communities that lack proper flood barriers. Even those that do have new flood barriers will see the defenses tested in real time — with a disastrous price for failure. A winter marred by many avalanche deaths could make way for a spring that brings many more flooding casualties.

This entry was posted on Monday, April 21st, 2014 at 2:20 pm and is filed under Flood Protection. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.