Spring Flooding Risk Increases

Posted at 8:38 PM, Mar 06, 2014
and last updated 2014-03-06 21:01:26-05

GRAND RAPIDS, Mich. (March 6, 2014) —  A very cold and snowy winter, a record-setting snow depth in March, as well as ice-covered rivers are combining to elevate the threat of river flooding in the coming weeks.

On Thursday, the National Weather Service in Grand Rapds issued their second spring flood outlook. You can access the full reportHERE.  Because the report is fairly technical and lengthy, here are some of the bullet points:

  • The water content of the snow currently ranges from 3.5 to 7.0 inches to the north and 1.8 to 6.0 inches to the south.  These amounts typically occur once every 25 to 50 years.
  • Precipitation is expected to be near normal through May.
  • Soil moisture is above normal.
  • Most areas have a higher risk of any type of flooding when compared to the first outlook on February 21.

Here are the categories of flooding:

  • minor flooding is defined as causing little if any damage.
  • moderate flooding is defined as some flooding of buildings and roads, as well as the possibility of evacuations.
  • major flooding causes extensive flooding of roads and buildings. Large-scale evacuations are likely.

On the Grand River, the risk of flooding at these locations is as follows:

  • Grand Rapids:  90% chance of minor flooding (up 12% from February);  41% of moderate flooding (up 3%) ; and 18% chance of major flooding (no change).
  • Ada:  86% chance of minor flooding (up 10%);  52% chance of moderate flooding (up 9%);  10% chance of major flooding (up 3%).
  • Lowell:  92% chance of minor flooding (up 11%);  30% chance of moderate flooding (up 3%);  6% chance of major flooding (up from less than 5%)
  • Ionia:  83% chance of minor flooding (up 8%);  35% chance of moderate flooding (up 2%);  6% chance of major flooding (up from less than 5%)
  • Portland:  29% chance of minor flooding (up 9%);  less than a 5% chance of moderate or major flooding.

It’s interesting to note that last year’s record flood stage in Grand Rapids was 21.85 feet, which is technically just “moderate flooding.”  According to the recent outlook, there is a 41% chance of the river rising to moderate stage, which is 21.0 feet and less than a foot below last year’s record.

This is not an immediate concern, but it will be something to be keeping an eye on over the next few weeks.