Larimer County Spring Run-off Information

Everyone in our region is worried about the run-off this spring. The floods changed the topography of our rivers and streams which could also change the behavior of the water produced by melting snow. Although no one can really predict the outcome, there are a few resources we can access to track this spring’s runoff. Local Lyons meteorologist, Greg Berman has created a great Facebook page called the Flood Watch Network. This page will use local spotters and scientific monitoring to track any potential flooding activity in real time. If you’re on Facebook, please “like” the Flood Watch Network to receive these valuable updates.

Larimer County posted some information in their recent spring newsletter regarding spring run-off:

The snowpack in some areas is about 150% of average which generates concern for spring run- off volumes. Residents should prepare for flooding. Information is posted on the County’s web- site at www.larimer.org/flooding2013 on spring runoff awareness.

• Residents in areas where stream channels have moved or significant debris and sedimentation has occurred (particularly in the Front Range foothills in Boulder, Larimer, and northern Jefferson Counties) should be prepared for localized spring snowmelt flooding.
• A small amount of water could start moving large quantities of sediment in affected streams. Debris flows may obstruct stream channels and cause flood issues. The September 2013 rains likely destabilized hillsides and steep slopes so increased landslides and rock slides will also be possible this spring particularly with heavier or prolonged rainfall.
• More significant flooding will likely occur this spring if rain falls on the snow, rapid warming occurs and if there is more snow between now and the melt.
• The early March snowpack in the mountains of the Big Thompson River and St Vrain Creek drainages is right up there with the highest snowpack years (in the past 35 years) of 1986, 1996, 1997, and 2011. How fast the snow melts and when, rainfall timing and amounts will also be very important. For example, in the springof 2011 there were concerns due to the high snowpack, but the snow melted out in an orderly fashion without major issues.

source: Larimer County Spring Newsletter