The strong storms Wednesday produced a brief “spin-up tornado” near Mechanicsville in St. Mary’s County, Maryland.
The EF-0 tornado had an estimated wind speed of 85 mph, covering some 3.3 miles and a width of about 75 yards.
The start of the severe storm was the result of a cell merger between two separate thunderstorms that approached St. Mary’s County between 8:42 and 8:47 p.m.
— NWS Baltimore-Washington (@NWS_BaltWash) June 10, 2022
One storm crossed eastward over the Potomac River from near Quantico, Virginia, toward Charles County, Maryland; the other one crossed northeast over the Potomac River from near Colonial Beach, Virginia.
The cells then merged over central Charles County between LaPlata and Dentsville, then proceeded east toward northern St. Mary’s County, where the tornado occurred, the National Weather Service said.
The twister, which initially touched down in an area of residential houses, damaged some two dozen trees and large branches at the intersection of Maryland state Route 5/Point Lookout Road and Maryland state Route 235/Three Notch Road.
The trees fell to the north, east, southeast, east, west and northwest. One of the trees fell onto the roof of a residence, causing roof damage but no injuries.
“Due to the localized but prolific damage in this enclave, wind estimates are up to 85 mph.
It is believed that the tornado went right over this enclave of residences due to the random direction of tree falls,” the National Weather Service said.
Meteorologists said the tornado may have lifted as it moved east-northeast, but tornadic damage was observed some 3 miles further east of the initial touchdown, along Delabrooke Road, where a “chaotic mix” of downed trees and branches were seen in a forested area, the National Weather Service said.
Although most of the damage was sporadic and isolated, it included snapped tree trunks and some uprooting. The storm’s wind speed is estimated between 60 to 70 mph, based on tree damage, according to the National Weather Service.
Spin-up tornadoes are fast-moving tornadoes that form not from a supercell but from lines of thunderstorms, National Weather Service Science Officer Seth Binau told Ohio station WBNS. Most of these types of twisters happen in the Ohio Valley.
The agency concluded the damage surveyed in Columbia were caused by straight line wind damage due to a downburst from a severe thunderstorm, which can cause “tornado-like damage.” According to the storm survey, the severe weather took down hundreds of trees and wires near Atholton Park to Oakland Mills. Two hardwood trees were also uprooted near Kendall Ridge.
The downburst averaged wind speeds of 75 mph and lasted up to 10-15 minutes.