WASHINGTON (AP) _ In 1900, a hurricane slammed into Galveston, Texas, without warning, killing as many as 8,000 people. Such storms can no longer sneak up on major cities, thanks to technology celebrating its 40th anniversary today.

The first weather satellite took to the sky on April 1, 1960, sending back a fuzzy gray cloud image that forever changed the way we look at the weather.

``The fact is, the satellite is indeed the primary observing system in the tropics. I just can't imagine doing our job now without'' it, said Max Mayfield of the National Hurricane Center in Miami.

``Just the simple fact that people can see the hurricane threat every day on television now'' helps them understand the threat, he said.

Today the blurry first image has been replaced by a stream of brightly colored images tracking hurricanes, pinpointing twisters and measuring the power of El Nino and the drift of volcanic ash.

``What weather satellites represented was putting a sentinel in a guard tower up above the Earth,'' said Jamison Hawkins, chief of services at the National Weather Service's Office of Meteorology. ``The atmosphere is a jigsaw puzzle, and without satellites we have a lot of pieces missing.''

The Weather Bureau, as the weather service was known then, didn't pick up the Galveston storm until water was lapping over the docks, Hawkins said.

Four days before the hurricane destroyed Galveston, there had been reports of a storm in Cuba, but no one believed it could cross the Gulf of Mexico, he said. ``If we had had a satellite, imagine.''

``Compare that with Hurricane Andrew, where we drew a bead on that storm over a week in advance when it was a cluster of thunderstorms out in the Atlantic ... It caused $30 billion in damage and only 14 people died,'' Hawkins said. The 14 deaths were direct storm fatalities in Dade County, Fla. The final toll including other states was about 40 deaths in the storm, still remarkably low.

Former National Hurricane Center director Robert Sheets once said that if he had only one tool to do his forecasting job, it would be the geostationary weather satellite.

And today's satellites do more than just show cloud tops. They measure radiation from the ground and air, allowing scientists to take the temperature below; they can sense water vapor in the air, indicating where clouds and storms may form and they can even track plankton in the ocean.

In the case of deadly tornadoes in Oklahoma last May 3, satellites showed moisture boundaries, telling forecasters that conditions were right for powerful storms to form, recalled Hawkins, who worked at the National Environmental Satellite, Data and Information Service before joining the Weather Service. NESDIS operates the nation's weather satellites.

And severe weather isn't the only use for satellites.

Marine and aviation programs also rely on information collected by weather satellites covering huge expanses of ocean.

``We see the jet stream, we see the Gulf Stream, we see the interaction of the ocean and the air,'' Hawkins said. ``In short, it is a workhorse we find absolutely entwined in every forecast process we now conduct.''

That first satellite _ Tiros _ quickly revealed the value of watching weather from on top.

Meteorologists saw that clouds banded together in strange ways they had not expected. Patterns emerged that helped them make better predictions. Even strange upward lightning strokes were discovered _ a phenomenon long rumored among pilots but never before recorded scientifically.

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On the Net:

National Weather Service: http://www.nws.noaa.gov

National Environmental Satellite, Data and Information Service: http://www.nesdis.noaa.gov

National Oceanic and Atmospheric Administration: http://www.noaa.gov

First image is at: http://www.ncdc.noaa.gov/pub/data/images/tiros1.gif

First launch is at: http://www.photolib.noaa.gov/lb_images/space/spac0046.htm

Satellite images from NCDC are at: http://www.ncdc.noaa.gov/ol/satellite/olimages.htmlH