The accident was reported at about 3:20 p.m. on the northbound parkway between Exits 29 and 31, the Connecticut Department of Transportation said. The right lane was closed.
Traffic was moving slowly approaching the Lake Avenue exit after the crash, DOT said.
Greenwich Police and Fire were on the scene of the rollover. The pickup truck was fitted with a snow plow on the front. The accident occurred as flurries were flying in the area.
It was not clear how long it would take to clear the roadway.
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