Ag Weather Forum
Doug Webster DTN Senior Ag Meteorologist

Thursday 11/29/12

Snow Cover's Importance to Winter Wheat

Arctic cold is a common occurrence across the Canadian Prairies during the winter as it slides southward from the Yukon and the Northwest Territories from time to time. The degree and persistence of this extreme cold can vary considerably from year to year depending on the overall weather pattern that sets up.

Winter wheat has shown some increase in acreage across the Prairies during the recent few decades and its survival during the winter depends quite a bit on how much snow cover exists during periods of cold weather. Snow cover acts as a warming blanket and is an excellent insulator.

Research done by North Dakota State University and the U.S. Department of Agriculture show that only a few inches of snow can greatly benefit winter wheat during times of cold. It is generally accepted that 3 inches (8 cm) of snow can prevent winterkill, but that 4 to 6 inches (10 to 15 cm) of snow depth will further reduce winter injury.

Soil temperatures at crown depth have been shown to be as much as 30 to 35 degrees F higher with 2 to 4 inches (5 to 8 cm) of snow cover while readings of 40 to 55 degrees F higher can occur with 5 inches (13 cm) or more of snow. The study was based on air temperatures of minus 22 to minus 40 F (minus 30 to minus 40 C), which are temperatures seen several times during a typical winter across the Canadian Prairies.

When crown depth temperatures fall to minus 5 F (minus 21 C) or lower, we see a rapid increase in winterkill, but with a few inches of snow crown depth temperatures may only be a few degrees below freezing, allowing for a good survival rate.

Current snow depths across the central and southern Prairies are in the range of 2 to 8 inches (5 to 20 cm) with lesser amounts across southern Saskatchewan. Temperatures have been lower than normal during the past few weeks across the Prairies, but no extreme readings have yet to appear and most areas currently have enough snow to protect winter wheat.

A couple of low pressure areas moving through the region during the next week may add to the current snow cover and we are not expecting any extreme cold in the short term. Beyond 10 days, there are signs that some arctic air may arrive and send temperatures to well below zero F (minus 18 C). Hopefully we will continue to have the protective snow cover for winter wheat still in place.

Doug Webster can be reached at doug.webster@telventdtn.com

(BA/ES)

Posted at 10:38AM CST 11/29/12 by Doug Webster
Post a Blog Comment:
Your Comment:
DTN reserves the right to delete comments posted to any of our blogs and forums, for reasons including profanity, libel, irrelevant personal attacks and advertisements.
Blog Home Pages
January  2015
S M T W T F S
            1 2 3
4 5 6 7 8 9 10
11 12 13 14 15 16 17
18 19 20 21 22 23 24
25 26 27 28 29 30 31
Subscribe to Ag Weather Forum RSS
Recent Blog Posts
  • Arctic Air to Bring Chilly Weather Back to W. Canada
  • Dryness Concern Grows in Southern Plains
  • Brazil Rain Update
  • Mild, Dry Weather Regime Well-Established in W. Canada
  • Limited Western U.S. Snowpack Forecast
  • Global Temps Set New Record Warm Levels in 2014
  • Above-Normal Temperatures Bring Relief to Western Canada
  • Brazil Soy Estimates May Have Maxed Out
  • Very Cold Pattern Breaks Down in W. Canada
  • Favorable South America Weather Pattern
  • Mild Midsummer Pattern Possible for Midwest Corn Crop
  • Variable Winter Weather to Continue
  • Limited Corn Belt Soil Moisture Issues
  • Ice Box Takes Hold Across Canada
  • California Drought Rundown
  • Cold Air to Make a Return to Canada
  • A Look at 2015 Growing Season
  • Mild Pattern To Last Another Week For Canada
  • North America Was Cool Spot In November
  • Southwest Plains Still Need Precip