Congress will spend more than $2 million to upgrade weather-monitoring equipment in areas prone to hurricanes, National Weather Service officials said.

The government’s equipment for monitoring wind speed is run by electricity without backup and often fails during storms, weather service officials said. Hurricane Katrina knocked out power to much of the Gulf Coast as it came ashore last August, leaving meteorologists, homeowners and insurers without a clear picture of the storm’s ferocity.

Some homeowners have been denied claims on wind-damaged homes based on questionable wind-speed measurements, they said.

“We’ve been needing to get backup power at those sites for some time,” National Weather Service spokesman Greg Romano said. “It’s unfortunate that it takes an event like Katrina to get the money to accelerate acquisition and install backup power for those sites.”

Installation of the new system could start in November. But Al Wissman, the weather service’s maintenance branch chief in Silver Springs, Md., said it will be at least two years till all systems are in place.

Researchers estimate Katrina’s wind speeds along the Gulf Coast at 125 to 145 mph. But instruments that remained in operation during that time show speeds far lower — as low as 67 mph at one inland location. Attorneys for homeowners denied claims and scientists said many of those measurements should be discounted because they came from instruments placed away from the coast or on the edges of the hurricane zone.

“A lot of them weren’t in that area. If they are, the power went out or something happened and they didn’t record anything,” said Mark Powell, an atmospheric scientist at NOAA’s Atlantic Oceanographic and Meteorological Laboratory whose team estimated Katrina’s winds at 140-145 mph. “Very frustrating. It’s actually something I’ve been complaining about since 1993 when they came out with these systems. They didn’t have any backup power and they needed to have it.”

Experts said Katrina’s Category 5 tidal surge did most of the damage along the Gulf Coast. But they don’t rule out the wind as a contributing factor to property damage.

The National Hurricane Center estimated sustained winds of 125 mph in Hancock County. But there would have been higher gusts pounding the coast and a waxing-and-waning of winds that might cause a fatigue effect on structures.

“It’s turbulent,” said Herbert Saffir, a structural engineer who developed the wind portion of the Saffir-Simpson scale. “It’s not smooth-flowing wind like you have in a wind tunnel where they’re testing aircraft. “It gets stronger and dies down a little and gets stronger, but it’s extremely turbulent. That’s one of the things that causes wind damage.”