The biggest relief effort in US education history was under way this week with schools in hurricane-hit New Orleans not expected to open this academic year.

Schools across the United States were scrambling to take in an estimated 170,000 displaced students and at least 20,000 teachers after Hurricane Katrina hit the Gulf Coast and floodwaters engulfed New Orleans.

Officials are grappling with a logistical nightmare, inundated with thousands of homeless students, many left with just the shirts on their backs and all records of their previous school work wiped out.

Many of New Orleans’s 126 schools are thought to have suffered the same fate as other city buildings, flattened by fierce winds or swept away or submerged when a storm surge breached a levee damming nearby Lake Pontchartrain. A full reckoning of the destruction will not be possible until floodwaters recede. Pumping out what has become a stagnant soup of industrial toxins, human waste and floating corpses from a death toll thought to be in the thousands is expected to take up to 80 days.

President George Bush met education secretary Margaret Spellings on Tuesday amid widespread criticism of the White House’s response to the disaster, and promised a plan to “help states absorb the costs” of admitting students fleeing the disaster zone.

In Baton Rouge, 80 miles north-west of New Orleans, the influx of students has already overwhelmed neighbourhood schools, leaving officials scouring churches and businesses as venues for makeshift classrooms. To cope with the crisis, the city’s education chief has been given emergency powers.

Roger Moser, Baton Rouge’s former school board chief, said the normally sleepy city had been swamped by 100,000 evacuees, turning it into a “madhouse”. Officials registering survivors huddled in basketball arenas and Salvation Army hostels have found 2,000 students, but were braced for “many, many more,” he said.

In Texas, creating temporary classrooms at the Houston Astrodome, home to the largest individual refugee encampment, was being considered. Lisa Bunse, of Houston independent school district, said dozens of Louisiana teachers among those sheltering at the 62,000-seat auditorium, have volunteered their services. Up to 20,000 teachers were uprooted from the state. Officials across the United States are being urged to waive bureaucracy and draft them into classrooms as quickly as possible.

Roughly 135,000 Louisiana students have been displaced, plus an estimated 35,000 from Mississippi, where 244 schools were in Katrina’s direct path, said local officials. Schools from as far afield as Washington state, in the Pacific north-west, are opening their doors to the students.

Efforts to place students have been complicated by the need to reunite many with parents they were separated from in the chaotic exodus from New Orleans, which saw survivors airlifted from rooftops or scrambling to board buses out of the stricken city.

US Education Department officials said tough testing targets would be eased for schools receiving the students. “We will welcome these kids and worry about the fine print later,” said Ms Spellings.

* newsdesk@tes.co.uk