Small cats total big losses in 2003.

Insurers learned last year that it doesn't necessarily take an event like the Sept. 11 terrorist attacks or Hurricane Andrew to produce major catastrophe losses. A seemingly endless stream of smaller catastrophes, from fires to hurricanes to hailstorms to blackouts, had nearly the same effect last year, as the $11.44 billion in catastrophe losses recorded through the end of November already place the year as the third costliest in the past decade.

The year began with three major winter storms that blanketed 15 states with snow and ice and caused $1.1 billion in property damage. Those were followed by two March windstorms that combined to produce $365 million in insured losses, according to Insurance Services Office Inc.

From April 4 through April 8, winter storms pummeled 10 states, producing 386,000 claims and $1.2 billion in insured losses.

That was followed by what Boston-based risk modeling firm AIR Worldwide called the largest severe thunderstorm losses in history. "Catastrophe 88," as the storm was known, wreaked havoc across much of the Midwest, covering 18 states May 2 through May 11 and resulting in more than $3.13 billion in insured losses, according to AIR.

The year's oddest catastrophe struck in mid-August, when a mysterious power outage immediately and unexpectedly crippled much of the Northeast, Midwest and parts of Canada. Though property damage related to the event was low, the outage triggered at least $75 million in claims, most of them on commercial policies with contingent business, civil authority or other interruption triggers. However, as investigators from the U.S. Department of Energy and the Canadian Ministry of Natural Resources are still searching to pin down an exact cause for the outage, which was believed to be related to faulty lines in Northeast Ohio, losses could still be either higher or lower, depending on the ultimate findings of liability and how it relates to individual policy language, said Robert Hartwig, chief economist for the Insurance Information Institute.

Despite the predictions of several major atmospheric scientists that 2003 would see larger than usual hurricane activity, the United States was spared direct hits by several of the largest storms, including Hurricane Claudette, which had weakened to a tropical storm by the time it hit Texas shores in July--though it proceeded to cause $80 million in insured losses.

But when a hurricane finally did make a direct U.S. landfall, it was a big one. With winds of about 100 mph, Hurricane Isabel hit the East Coast Sept. 18, causing significant damage and massive flooding, concentrated in the coastal Chesapeake Bay area and North Carolina's Outer Banks. Isabel's $1.18 billion in insured losses made it the most significant storm to hit the Eastern seaboard since Hurricane Floyd in 1999, which caused $1.8 billion in insured losses.

The fourth quarter kicked off with the largest catastrophe losses of the year, and what may yet prove to be the costliest fire disaster in U.S. history, as at least 10 major wildfires raged across Southern California in late October from the Mexican border to north of Los Angeles. The two largest fires, in San Diego and San Bernardino counties, combined to cause at least $2.04 billion in insured losses.