Hurricane Katrina knocked out real-time weather alerts for much of the Gulf Coast, according to officials from Internet weather service provider WeatherBug, a company that feeds data to the National Weather Service.

But NWS, WeatherBug and telecommunications company officials have labored to restore communications at stations that transmit weather information.

WeatherBug, which shares observations with NWS through a public/private partnership, reported that 50 percent of its weather stations were not functioning shortly after Katrina hit the Gulf Coast.

Additionally, NWS reported that most of the agency's weather radio transmitters were not emitting signals.

But as of last week, about 70 percent of the weather stations in areas hit by Katrina were functioning, WeatherBug officials said. As repair crews restore power and Internet service in affected areas, many stations are coming back online.

Officials said most of the malfunction issues in Louisiana, for example, were the result of power and communications outages. Initially, officials didn't know if the problems were because of outages or if Katrina had blown roofs off stations, said John Doherty, senior vice president of professional services at WeatherBug.

Sensors installed on top of WeatherBug's stations monitor 27 weather conditions, including humidity, wind direction and wind speed. More than 300 stations were in the hurricane's path.

"We want to go in and fill in the gaps," Doherty said. "The whole purpose is to be prepared for another storm or a chemical explosion. This is more preventive than anything else."

WeatherBug officials are building nine new sites to complete the network's coverage in New Orleans and Gulfport and Biloxi, Miss.

National Oceanic and Atmospheric Administration weather radios, which announce NWS warnings and forecasts in emergency situations, were not working because the storm damaged the radio transmitters' communications system.

Most of the automated stations were operational. But communications to the radios, which run on BellSouth and MCI landlines, weren't working, said Martin Garcia, an electronics program manager for NWS' Southern Region.

Only one of the NOAA weather radio transmitters was responding.

However, the MCI/BellSouth landlines were back up by Sept. 9, leaving only three NOAA weather radio transmitters without communications in Gulfport and Baton Rouge and Burris in Louisiana, Garcia said.

"The [telecom] companies have been doing an outstanding job out there," Garcia said. "That they were able to have them back up by Friday was pretty awesome."

At press time, NWS officials did not know when communications would return to the three sites, but they anticipated quick support from the telecom companies.

In Boothville, La., and at New Orleans' Lakefront Airport, however, NWS' automated weather stations are underwater, Garcia said. Sensors at those stations will have to be replaced or refurbished, officials said.