The “derecho” wind storms of late June and early July were the third-most expensive natural disaster in Ohio in 38 years. Only the tornado outbreak in Xenia in 1974 and the hurricane-borne winds of 2008 created costlier damage, according to an insurance trade association.

Statewide preliminary estimates put insured losses at $433.5 million to $440 million for the June 28-July 4 period, the Ohio Insurance Institute said.

“Any time there’s a huge amount of loss like that, of that magnitude, it’s a surprise,” said Mitch Wilson, an OII spokesman.

Wilson couldn’t say which areas of Ohio were hit hardest, but much of the damage focused on roofs and downed trees, as well as wind and rain damage to homes’ contents.

Damage from the Hurricane Ike wind storm four years ago exceeded $1.2 billion, while the 1974 tornado outbreak created $1 billion in damage. Both figures are based on 2008 dollars, the OII said.

A derecho is defined as a wall of intense and fast windstorms. The late June storm left a more than 700-mile swath of damage across parts of the Midwest and the East Coast, cutting power to millions, according to AccuWeather, of State College, Pa. Thirteen people were killed.

The National Weather Service said the storm covered 600 miles in 10 hours, while the weather service station in Wilmington put high-wind gusts at 80 mph in several communities, including Dayton, Coldwater and Gahanna.

Insured losses ranged from $20,000 to nearly $61 million, the OII said.

Ohio’s total damage from the June-July storms may well be higher, Wilson said. The $433 million figure is based on survey responses from 27 of OII member companies — companies which represent 76 percent of the auto coverage market in Ohio and 73 percent of the state’s home ownership market, he said.

Jamie Simpson, WHIO-TV meteorologist, has long noted that straight-line wind events need to be taken as seriously as tornadoes. While tornadoes can strike in a scattershot fashion, “straight-line wind events blow through and they hit everybody,” Simpson said.

Insurance watchers say the storms are part of an undeniable trend that will be felt when insurers calculate new rates.

“The derecho is just the latest in a multi-year string of events,” said Robert Hartwig, president and economist of the New York City-based Insurance Information Institute.

Nationally, there were about $9.3 billion in insured catastrophe losses in the first half of 2012, $8.8 billion of that due to thunderstorms and wind events, Hartwig said. That makes 2012, so far, the third most expensive year ever, he said.

While hurricane activity has been somewhat muted since 2008, it’s the Midwest and South that seem to be experiencing much of nature’s wrath, he said. He cited the 2011 tornadoes that hit Joplin, Mo. and Tuscaloosa, Ala.

This is the eighth “major natural disaster” to hit Ohio since 2011, according to Dan Kelso, OII president. The institute also counts two winter storms in 2011 and six “wind-hail” storms, it said in a statement.

Insurance companies cannot raise rates to recoup losses, and they aren’t permitted to attribute rate increases to single events, Wilson said. But they can take into account loss history and modeling predictions of weather patterns, he said.

The state Department of Insurance is charged with determining whether proposed insurance rates are appropriate, he said.

“The history of the losses are taken into account, without a doubt,” Wilson said.