The current record, AIR said, belongs to a severe weather system that struck during April 6-12, 2001. That storm system caused $2.2 billion in losses.

But this month's series of storm fronts that occurred the first two weeks of May was “one of the worst in meteorological terms,” Uday Virkud, senior vice president at AIR, a subsidiary of Jersey City, N.J.-based Insurance Services Office Inc., told National Underwriter.

“It is likely that the ultimate insured losses could exceed that $2.2 billion figure from 2001,” he said, judging from preliminary data and simulations the service has collected to date.

Over at the Insurance Information Institute Inc., based in New York City, the figures were lower, but no less catastrophic. Loretta L. Worters, vice president communications for I.I.I., said that as of the end of the business day May 14, total reported insurance losses stood at $1 billion and climbing as more information continued to come in. She added that the event would be one of the costliest tornado events on record, and possibly the costliest.

A series of storm fronts, beginning May 2, hit Kansas, Missouri and Oklahoma particularly hard, destroying homes and businesses. Some towns were completely destroyed and may never be rebuilt.

Ms. Worters said that the commercial insurance side appears to be a lot smaller than the personal property side that would include homes and automobiles.

Christopher L. Guidette, assistant vice president corporate communications for the ISO, said it expects to issue preliminary figures by early next week. He said many companies are still in the process of taking claims.

The National Oceanic and Atmospheric Administration said the storm period, May 4-10, produced 384 tornadoes in 19 states causing 42 deaths. The first ten days of May saw 412 tornado reports, NOAA added. The previous record was May 12-18, 1995, when 171 tornadoes were reported, it said.

The deadliest series of tornadoes was in 1925 when 805 people were killed, NOAA said.

In terms of insured, I.I.I. said the worst damage was in May 1999 when tornadoes cost insurers $1.6 billion adjusted to 2002 dollars.

Reproduced from National Underwriter Edition, May 19, 2003. Copyright 2003 by The National Underwriter Company in the serial publication. All rights reserved. Copyright in this article as an independent work may be held by the author.