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Snow Mold

Finally, it looked like spring was in the air.  The temperatures were on an upward trend and it looked like it may be safe to put my winter coat and boots away. We had snow overnight, so that thought quickly evaporated but luckily most of the snow also did. I had been feeling a bit more symptomatic and had mostly chalked it up to allergens in the air. It was officially spring after all. What I had not considered was the potential connection to the melting snow that was outside. Could one of the triggers that I was experiencing, be snow mold?

What is “snow mold”?

Did you know there is something called “snow mold”? I honestly had not even thought about this potential. I just assumed that it was too cold for mold. This winter was filled with a considerable amount of ice, snow, and cold.

Snow mold is a fungus that grows under the snow-covered organic matter and can spread at temperatures of 0°C and can live under the snow.1 It is thought to occur when the ground isn’t fully frozen or when snow remains after the ground has thawed, similar to a snow pile. We had lots of snow piles this winter and at one stage, had run out of places to put the snow. It is thought that the weight of the snow on the grass, in conjunction with winter moisture and the coverage of leaves, long grasses, etc. can create the perfect conditions for mold to grow. The two types of mold that are most likely the culprits are gray snow mold (Typhula blight) and pink snow (also called Microdochium patch or Fusarium patch).2

Exposure to allergens

Exposure to allergens can be very dangerous for asthmatics causing not only allergic symptoms of sneezing, itchy and watering eyes but also asthma symptoms of coughing, wheezing and chest tightness.3 It is important to follow your asthma action plan if symptoms occur. It may also help to ensure that lawn areas are cleared before the first snowfall to prevent any potential mold from growing. You can also check with your neighborhood garden center or horticulturalist about the application of lawn treatments to prevent mold, however, be careful of potential allergens in the lawn treatments.

Have you ever come across snow mold? Is this a concern in your neck of the woods? What ways do you prevent outdoor winter allergens?  Do you have any spring preparation that you do to prevent potential allergens that may be lurking? I would love to hear about your thought and experiences. Till then I wish everyone a great spring and hope that the cold weather is finally behind us for this year.

This article represents the opinions, thoughts, and experiences of the author; none of this content has been paid for by any advertiser. The team does not recommend or endorse any products or treatments discussed herein. Learn more about how we maintain editorial integrity here.

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  • JanetH
    10 months ago

    Yup, have seen the gray type here in south central Michigan. Looks disgusting. We don’t get it every year, and when we have, it’s in a small area. It doesn’t seem to bother me because the windows are still closed and I’m not out doing anything in the yard yet.

  • Shellzoo
    10 months ago

    Yes, I have heard of this. The local news mentioned this about a month ago just as I noticed my allergy symptoms had increased. In March my rescue inhaler use was more frequent and I developed eczema. Started feeling better the past couple weeks and now after seeing my doctor the eczema is getting better too. One point you made that I want to emphasize is making sure the yard is cleaned of leaves and such in the Fall. I did get my yard cleaned up last Fall but I live surrounded by oak trees and over the winter leaves had migrated into my yard and I suspect that mold developed from that.
    Thanks for this good information!

  • John Bottrell, RRT moderator
    10 months ago

    HI again Shellzoo. Yes, it was a nice article. Glad to hear that you’re feeling better. Never really thought of raking leaves in the fall as a way to prevent asthma triggers. I usually do it so it’s done and I don’t have to mess with it in the spring. But, you do make an excellent point. Thanks. John. Site Moderator.

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