Cambridge and Boston spent Sunday digging themselves out from under the two feet of snow left by the blizzard that struck all of the Northeast Friday.

Gov. Michael S. Dukakis told state employees working in Boston to stay home unless their jobs are essential, and the school department ordered public schools shut down for the day, as the city struggles to dig out from the record January storm.

Mayor Alfred E. Vellucci said yesterday Cambridge street crews did a "pretty good job of plowing" during the weekend, and estimated the total cost of the snow removal effort will reach $250,000.

The crews kept "all major streets open throughout the weekend," Charles F. Pacheco, traffic investigator for the City of Cambridge, said yesterday.

Pacheco added that the crews removed snow from parking lots, and churches, and tried to keep at least one lane of all side streets open on Sunday.

"Unusual wind and snow conditions" collapsed the air-suspension roof of the Bubble Indoor Tennis Courts at MIT Friday at 10 a.m., Ross H. Smith, MIT's director of athletics, said yesterday.

Accumulated snow depressed a section of the west end of the Bubble, and crews planned to deflate the structure and clear the snow from it, Smith said.

However, once the crew removed a light tower, the building's fabric roof sagged and ripped on the corner of a door frame.

The fabric roof then "settled slowly to the ground," Smith added, ripping further on two remaining light towers. however, 15 employee, said yesterday power was turned workers were able to get out of the building, he said.

Smith said the $170,000 structure, which enclosed MIT's four indoor tennis courts, would probably be repaired by June, at an estimated cost of $75,000.

Charles R. Chambers, an MBTA on all the Redline tunnel between Harvard Square and Kenmore Square Friday afternoon because people were walking on the subway tracks.

Chambers added that bus service was "cut right in half" in Cambridge on Friday and Saturday.

Logan airport was closed from 8 a.m. Friday until 12 p.m. Saturday as crews "struggled to clear six foot drifts from runways," Ronald C. Brimm, a Massport spokesman, said yesterday.

Brimm added one runway was open yesterday and most of the 35,000 passengers who had been inconvenienced by the storm were able to depart.

By Sunday afternoon, passenger volume had returned to normal, Brimm said