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Extension > Extreme Weather > Flood & Water > Wet fall > Watch for hay fires following the flood

Watch for hay fires following the flood

There was a large amount of stored hay that experienced flood waters during the epic rainfall on September 22 and 23.  Water depth reached as much as three feet in some cases completely saturating bales.  While water itself does not necessarily affect the quality of the hay, high moisture levels lead to microbial activity that starts a decomposition process in the hay.  Symptoms of this process include mold, mildew, steam, musty smell, and heat. 

Investigations of hay that got flooded on Wednesday revealed that it had already gone out of condition by Monday.  In many cases this hay is already beyond usability from a quality standpoint.  In some instances it is getting hot enough to spontaneously combust. 

Farmers that have flooded hay should follow these steps: 

  1. Remove tarps to accommodate drying and cooling
  2. Remove good hay so that it does not spoil.
  3. Move wet hay so that it does not pose a fire hazard to its surroundings.
  4. Monitor borderline hay to ensure that it is not experiencing problems. 

Hay should be below 20% moisture to ensure long term storage.  Hay temperature is easier to monitor than moisture.  It is normal for hay to be above air temperature.  If the temperature exceeds 120 F it needs to be monitored closely, and if it exceeds 150 F it is a threat to combust.  Moisture and temperature monitors are available commercially, but temperature can be monitored by simply mounting a thermometer on a stick and inserting it into the hay.     

Bad hay can be disposed of by spreading on fields, or by allowing to compost.  In addition (ironically) it can be disposed of by burning if you obtain a burning permit.  If you have questions or would like more information you can contact your county Extension Office.  In Steele County the phone number is 444-7685, in Rice County the number is 332-6109.

For more information, contact:
Brad Carlson, County Extension Educator
1900 Fairgrounds Drive #17
Faribault, MN  55021
Phone:  507-332-6109, Northfield 507-645-9576, Lonsdale 507-744-5185
Fax: 507-332-9070

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