Watermelon Snow #733627 - Ask Extension

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Watermelon Snow #733627

Asked November 09, 2020, 3:55 PM EST

Hi! I live in Anchorage, near OMALLEY & Lake Otis Pkwy. Yesterday. red snow appeared on the snow when the snow turned to rain. I thought watermelon snow after looking it up, but as we are at sea level is it possible? Is it pigment from the leaves? It only appeared near trees.

Anchorage County Alaska

Expert Response

Good Afternoon,

This could be algae, such as the pink snow phenomenon.  It is known to occur here in Alaska.  Here is a brief description excerpt - "The algae, which grow best in temperatures less than 50 degrees Fahrenheit, lie dormant beneath the snow through the winter. During the spring melt, they awaken and feed off the flow of nutrients from thawing boulders, soil, insects, and trees. The algae use the fuel to propel themselves, with tail-like structures called flagella, to the surface of snow. Once they reach the top of the snowdrift, they lose their tails and compact together, creating a swath of color."

Since this is occurring beneath trees and is arising as the snow melts, this would be a likely reason for the color of the snow.  However, there could be other reasons, such as accumulation of a dusty residue from a nearby source.  I don't have a definitive answer for you, but I hope this helps.

Best Regards,
Casey


Casey Matney Replied November 09, 2020, 4:55 PM EST

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