LSU studied the weather effects of Hurricane Maria on Puerto Rico and found temperatures increased two degrees on average and humidity dropped five percent a month after landfall as a result of defoliation.
Satellite imagery showed Maria stripped the island of its vegetation, and LSU Coastal Sciences Professor Paul Miller says those plants usually absorb a lot of the sun’s energy, but with less foliage, more energy stuck around in the air.
“When you strip away all of the vegetation then the sun’s energy is not being used to make plants sweat anymore, and the result is that all of the energy is being used to increase the air temperature.”
Temperatures returned to normal about two months afterward when the island re-greened, but the effects may be more persistent outside of dense tropical rainforests.
Two degrees may not sound like much, but these recently discovered hurricane side effects can add up. Miller says in May the National Weather Service issued heat advisories for the Florida panhandle, which is still recovering from last year’s Hurricane Michael.
“(The NWS) said hey we’re expecting high temperatures over this area to begin with, but we think they are going to be a little warmer over the places where (Hurricane) Michael went.”
The study found the effect was not just limited to a major storm like Maria, they found similar scaled-down effects from Hurricane Irma’s passing just weeks before Maria.
Miller says they discovered another side effect of hurricane defoliation; river levels increased, and water quality dropped.
“Without the tree canopy you had more water making it into streams and rivers, and that water also tended to be much muddier and more brown.”