By Paul Tennant
---- — LAWRENCE — The region was expected to get a stray thunderstorm early yesterday evening, but the torrential downpour that drenched the Merrimack Valley surprised just about everybody.
In Lawrence, Exeter and Phillips streets were so flooded they were impassable for part of the evening. Andover Street also received a lot of water.
“A lot of heat, a lot of humidity” brought about the storm, according to Ryan Breton of Atkinson, N.H., a meteorology major at Pennsylvania State University who founded the website AtkinsonWeather.com.
“I think a lot of people were surprised by the lightning,” Breton said. The turbulence began as a relatively small thunderstorm over Andover and Tewksbury at around 6:30 p.m., then quickly headed east, he noted.
“It kind of came out of nowhere,” he said. Parts of Andover, Topsfield, Boxford and Rowley were struck by hail, he said.
The temperature shot up to a high of 94 degrees at Lawrence Municipal Airport, Breton said. Yesterday’s humidity produced a heat index — what the temperature feels like, the reverse of the wind/chill factor – of 98. Boston was slightly hotter, with a high temp of 95 and a heat index of 100, according to Breton.
The lightning triggered a few house alarms in Andover, police Lt. Lee Britton said. Georgetown police reported one street in the town temporarily lost power.
A tree fell on a car on Lincoln Street in North Andover, but the driver was not injured, police in that town said. Lightning struck a chimney in Methuen, but serious damage did not result, police said.
Police in Salem and Plaistow, N.H., said their towns did not sustain serious storm damage. Farther up north in the Granite State, however, 23 Boy Scouts and three adult leaders were injured by lightning at a camp in Gilmanton Iron Works.
Scouts spokesman Greg Osborn said no one was directly hit by the lightning at the Griswold Scout Reservation. Firefighters said the lightning struck near where the Boy Scouts had gathered at Camp Bell. They were under shelter at the time, Osborn said.
Some of the victims complained of tingling and burning sensations and all were treated by camp nurses before being checked out at a hospital as a precaution, he said. Those who were treated are doing well and in good spirits, he added.