The Tuesday storms and tornadoes that killed at least 55 people in six states were classified as a catastrophe yesterday by the Insurance Services Office, in Jersey City, N.J.

Gary Kerney, assistant vice president, Property Claim Services for ISO, said that “PCS assigned catastrophe serial number 27 for damage caused by wind, hail, tornadoes and flooding in Alabama, Arkansas, Kentucky, Mississippi, Tennessee and Texas.”

He said PCS will continue to monitor the situation and added, “It is too early to estimate the extent of insured property damage.”

PCS assigns a catastrophe designation to events that cause more than $25 million in damage and have a major impact on policyholders and insurers.

Farmers Insurance Group said yesterday it will move additional people to the parts of Arkansas, Illinois, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Oklahoma, Tennessee and Texas that have been impacted by the severe weather.

Additionally, the company said it is advising customers to call its claims hotline if their homes have suffered damage from hail and wind storms, or were damaged by the tornadoes that hit Arkansas and Tennessee. The company said its Mobile Catastrophe Claims Center bus is already en route to the hardest hit areas.

As of yesterday, Farmers said it had already received more than 400 claims related to the severe storms.

In addition to Farmers, liaisons for the Federal Emergency Management Agency have been sent to state emergency operations centers in Tennessee, Kentucky and Mississippi, and the Atlanta-based Federal Incident Response Support Team has been deployed to Lafayette, Tenn., 60 miles northeast of Nashville.

The Tennessee Emergency Management Agency reported 26 fatalities, more than 100 injuries, and damage and/or power outages in at least nine counties across the western two-thirds of the state. Interstate 40 was closed for a time after 25 tractor-trailers were blown over, and more than 45,000 customers were without power as of 6 a.m. Wednesday, according to FEMA.

Kentucky reported seven fatalities and damage in at least four counties, and Mississippi reported damage in three Memphis-area counties, FEMA said.

Air Worldwide in Boston, the catastrophe modeling firm noted that the national Storm Prediction Center collected more than 70 reports of tornadoes, though the actual number of individual events is probably fewer.

Air meteorologists said they analyzed the SPC data and, based on time/space continuity of the reports, defined 25 individual tornados. In addition to the tornado reports, the SPC has recorded near 200 reports of straight-line winds and 112 reports of hail. There were several reports of hailstones the size of softballs.

In Tennessee, which suffered the worst damage, 15 students at Union University were trapped in their dormitories as shattered window and ceiling debris from a hard-hitting tornado prevented their escape.

Approximately 40 percent of student housing buildings were destroyed, and classes at the university have been canceled for the next two weeks for cleanup.

In Jackson, Tenn., collapsed wreckage trapped fifty residents inside a retirement home. Tornadoes also pulled a roof off a hangar at the international airport in Memphis. Forty miles outside Nashville, a tornado that struck a compressor station set off a natural gas fire that could be seen in the sky for miles around.

In Arkansas, a tornado overturned trucks on Interstate 40. Thirty homes were destroyed in Atkins, prompting the Red Cross to put up shelters. Officials in Gassville, Ark. sealed off the entire town after concerns that storm-related gas leaks would result in an explosion. A damaged hospital in Mountain View was forced to close its emergency room.

In Muhlenberg County in western Kentucky, storms killed at least three people at a mobile home park.

A downpour that started in Evansville, Ky. flooded major roads, causing street crews to barricade road access. Officials in surrounding counties reported heavy rains, downed trees and additional flooding.

In Lafayette, Mo. two industrial buildings, several homes and a church were destroyed by tornado winds, and in Ozark, Mo. there were reports of softball-sized hail.

This article updated 9:35 a.m.