A water main break beneath the highway opened up the sinkhole just after Exit 106 in the southbound lanes, State Police said, forcing authorities to close two lanes. Troopers said drivers should expect major delays on the interstate through the Methuen-Haverhill corridor and on interchanges at Routes 213, 110, 97, and 125.
Officials expect to have the water main repaired Monday night. Crews can't begin roadwork repair until then.
MassDOT said they hope to reopen the two closed lanes on I-495 by Tuesday night after evening rush hour.
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