Hurricane Irene’s visit to New Haven was shorter than expected, but it did linger long enough to knock down about 1,250 trees, flood several major roads and leave a quarter of homes in the city without power.

With Mayor John DeStefano Jr.’s lifting this afternoon of the mandatory evacuation order he issued Saturday for the Morris Cove neighborhood, the final chapter of the Irene story began: a massive cleanup effort that is likely to stretch late into the week. As of Sunday evening, about 17,287 homes lacked power and the city had deployed a dozen crews to remove fallen trees from the approximately 30 roads that remained obstructed throughout the city.

At a press conference on Mansfield Street, DeStefano said he has been informed by United Illuminating Company, the main electricity supplier to Greater New Haven, that power outages in the city would likely be “sustained,” but exactly how long homes will be without power remains unclear.

Because six school buildings remain without power, New Haven Public Schools will remain closed until Wednesday, DeStefano said.

Only seven households have reported serious property damage, he said, adding that the city’s data is still incomplete. The city’s most pressing concern in the cleanup effort, he said, is the tree debris that continues to make some of the city’s roads impassable.

The city’s crews and private crews contracted by the city, who will work through the night into Monday, will focus on removing debris from arterial routes before attending to power lines tangled up in fallen trees and tree branches. Trees within parks are the city’s lowest priority, city spokesman Adam Joseph said.

The city has set a goal of clearing all arterial routes in the city by Monday morning, DeStefano said.

The city is coordinating with the University to help clean up the area surrounding Yale’s campus. DeStefano said he spoke to University President Richard Levin Sunday to plan for Yale groundskeeping staff to assist city crews in removing debris, though he declined to discuss the details of the arrangement.

In general, DeStefano said, the city’s response to Irene was an improvement over its much-criticized handling of the heavy snowstorms that left parts of the city impassable for several days in January. The city was better able to directly communicate with residents about what precautions to take in anticipation of the storm, and aldermen made more effective use of constituent email lists and social media to keep residents informed.

By Sunday afternoon, it was clear that New Haven had been spared the worst of Connecticut’s encounter with Irene, which was downgraded to a tropical storm before it made landfall Sunday morning.

Three beachfront houses in East Haven were destroyed and pulled out into the Atlantic Ocean, while dozens more were severely damaged. Two residents of a severely damaged East Haven home remain unaccounted for, and a Bristol resident is also missing.

In Bristol, rescuers from the National Guard, which was deployed by the hundreds throughout the state, rescued one of three men whose canoe had capsized in the Pequabuck River, while another man swam to safety and the third, Shane Seaver, never surfaced, the Hartford Courant reported.

Irene’s Connecticut death toll stands at two, including Seaver and a woman in Prospect who died in a house fire caused by downed wires, according to the Courant.

More than half the state — about 775,00 homes — currently lacks power. About 2,000 residents remain in emergency shelters throughout the state. While the storm delivered only about three inches to New Haven, parts of western Connecticut received over eight inches.

Gov. Dannel Malloy spoke publicly about the beating the state’s coastline took from Irene after visiting Beach Street in West Haven and Cosey Beach Avenue in East Haven, where significant property damage was reported. The state has licensed an additional 1,900 insurance adjusters from out of state to expedite assessments for homeowners who have experienced property damage during the storm, bringing the total number of adjusters to 5,000, insurance commissioner Thomas Leonardi said.

“After touring some of the hardest-hit areas in East Haven and West Haven personally, it’s clear we have our work cut out for ourselves as we begin to fully grasp the damages associated with this storm,” Malloy said in a press release.

Transportation will likely be in a state of paralysis for several days.

Power lines fell onto MetroNorth rails in New Canaan and tree branches littered the rails from New Haven to New York, making it unclear when service, which was suspended Saturday, will resume. The Tappan Zee Bridge, used by many commuters to New York City, is likely to be closed for several days. Around noon on Sunday, however, Malloy reopened the Merritt and Wilbur Cross Parkways. CT Transit service will be back on schedule in New Haven starting at 7 a.m. on Monday.

Malloy is scheduled to brief the media on the aftermath of the storm and the state’s continued response Monday at 10 a.m.

Update: 6:07 p.m.

An earlier version of this story reported Irene’s Connecticut death toll as one, because Shane Seaver had not yet been confirmed dead. His body was recovered from the Pequabuck River in Bristol at 11 p.m. Sunday night, bringing the storm’s death toll to two.