Monday, July 3, 2017

Minor Natural Disasters: Summer '17

Accumulating hail, the day after the storm. Horsebarn Hill, Storrs, Ct, June 28, 2017.

Things have been just a tiny bit apocalyptic here in northeastern Connecticut this summer. Last Tuesday there were some impressive thunderstorms around in the evening, and even a bit of hail on and off for about 10 minutes at my house. The hail was pea-sized, and it all melted about as quickly as it fell, which is pretty typical for this part of the country, where even that level of thunderstorm severity is uncommon. The next morning, though, I discovered that the storm hit much harder around the UConn campus. 

The biggest hailstone I could find, about 2 cm in diameter. The top half has melted off, so the internal layering is visible.
 Along the roads approaching campus, I started to see piles of hail that had survived a fairly warm summer night. There were plenty of dime-sized hailstones and even a few nickel-sized specimens. In some shady spots, the frozen piles persisted until lunchtime. I've never seen a storm like that in the East, though I have experienced comparable accumulating hail events in New Mexico and Wyoming.

Yellow Pitcher Plants (Sarracenia flava) outdoors at the UConn greenhouses were moderately shredded.
The storm was bad enough to cause noticeable damage around UConn, where the worst hail occurred. The vegetation was generally a bit torn and bruised, and there was a layer of shredded leaf fragments under some trees, though everything still looked pretty green from a distance. There wasn't any structural damage to buildings around campus, as far as I could tell, though I suspect that the storm was pretty close to the severity that would have dented car roofs and broken glass at the greenhouse.

Gypsy Moth-defoliated trees in Gurleyville, Mansfield, Ct, June 2017.
Eastern Connecticut has been the site of another, slower but more ecologically serious, tree-damaging phenomenon this year: the worst Gypsy Moth outbreak since the 1980s. The caterpillars have been incredibly numerous this year, after a couple of years of increasing Gypsy Moth populations and a very mild winter, and there are large areas of woods that have been defoliated to the point where they look like what you'd expect in April, before the trees have leafed out. 

Hundreds of Gypsy Moth caterpillars on a Pin Oak in Woodstock, Ct. Most have been killed by disease.
Fortunately, there are signs that the current outbreak is just about finished. Gypsy Moths tend to come and go in cycles, becoming problematic for a time, but then virtually disappearing for a decade or more as various diseases and parasites catch up to them. The past few weeks I've been noticing more and more mushy, dead caterpillars on tree trunks; these are probably victims of a fungus, Entomophaga maimaiga. Some Gypsy Moths do seem to be surviving and are entering their pupal stage now, but with any luck the trees will leaf out again soon and the moths will not be able to return in significant numbers in 2018, or for many years to come.