BRASS has collected knowledgeable persons from around the area to be a "panel of experts" able to respond to your questions. So, send us a question about rivers, birds, fish, amphibians, mammals, weather, plants, invasive species, local history, farming, geology, toxins in stormwater, etc. by mail, phone or email (rulmer@co.essex.ny.us).
Q: When a whirlwind on Saturday, May 4, grabbed up all our mulching hay and deposited it in the top of trees, was that a "microburst"?
A: (Gregory Hanson from the National Weather Service) "As I recall, Saturday was a dry, sunny day, with no showers or thunderstorms around. So it wouldn't be a microburst you saw, but just a whirlwind (or dust devil). Those are characterized by rapidly rising air, rather than the falling air in a microburst. In a whirlwind, a parcel of air at the surface is warmed and begins to rise. Any little eddy or whirl in the air (we call it vorticity, ‘cause we have to justify 4 years of college) gets stretched out vertically as the air rises. As this happens, it spins faster, like an ice skater bringing her arms in and spinning faster.
"Microbursts (or downbursts) are fast outrushes of rain cooled air from a thunderstorm or just a rainshower. When the first batch of rain initially falls, it pulls cool air along with it and cools the air below the thunderstorm through evaporation. The cooler air is much heavier than the warmer air it is moving through, so it accelerates downward. Once it reaches the ground, it spreads out sideways, and can produce damaging winds."