Scenes of destruction in the storm's path across Florida showed why more than 600,000 in Pinellas and Hillsborough counties were ordered from their homes, Tampa Mayor Pam Iorio said Saturday.

When future storms come, local officials expect lessons learned from Charley to make evacuations more effective.

``What we saw of this storm was a very sobering lesson about how hurricanes can change course,'' Iorio said. ``Next time it could change from a probable course and hit us.''

The power to declare evacuations rests with local government officials. The mechanics of making that decision - whether it's a county commission or mix of local officials who decide - may differ, but the guiding factors are similar throughout the state.

A storm's intensity, its projected track and the level of flooding expected in coastal and low-lying areas are among factors officials consider.

Storm models help establish five levels of evacuation zones. The greater a storm's intensity and expected flooding, the farther the evacuation area spreads from the coast and other bodies of water.

In Pinellas, the county commission determines who should evacuate and when, based on recommendations from the county administrator.

In Hillsborough, a committee of officials including the sheriff, three county commissioners and the mayors of Tampa, Temple Terrace and Plant City declare a local state of emergency. That allows the county administrator and emergency management leaders to start evacuations.

With Charley forecast Thursday to become a category 3 hurricane, which has winds up to 130 mph and a storm surge as high as 12 feet, Pinellas and Hillsborough ordered evacuations of the first three evacuation zones.

Charley ended up coming ashore near Punta Gorda as a category 4 storm, which has winds up to 155 mph and a storm surge as high as 18 feet.

The local evacuation area could have stretched to the fourth zone had Charley gained strength sooner, said Dennis LeMonde, Hillsborough's emergency management spokesman.

The Hillsborough evacuation area included about 300,000 residents; in Pinellas, it included 350,000. How many people actually left was unknown. Hillsborough shelters reported housing about 8,000 people, and Pinellas shelters served about 8,400.

Some Bay area residents evacuated to areas that ended up being in Charley's path, but local officials didn't regret asking them to leave.

The decision to evacuate must be made early enough to give people time to leave and must be based on forecasts, not hopes that a storm will turn, LeMonde said.

``You would have to be second-guessing Mother Nature to know that,'' he said. ``Safety is the overriding issue.''

The evacuation itself was relatively orderly, with no significant traffic tie-ups on area interstates before the storm, said Marian Scorza, a Florida Transportation Department spokeswoman.

The biggest concern was the number of people who didn't leave, Pinellas County Administrator Steve Spratt said.

Local law enforcement didn't force people to leave, but instead focused attention on people who wanted help.

Spratt said too many mobile home residents refused to go, some saying they wouldn't leave their possessions and others saying they had ridden out storms before.

``That can be a deadly decision,'' said Spratt, a survivor of Hurricane Andrew's sweep across South Florida in 1992. ``We were staring down the bullet of a 140 mph hurricane. [Evacuating] is a precaution you have to take.''

To try to overcome residents' reluctance to leave, Spratt plans to hold meetings at Pinellas mobile home parks to illustrate how Charley flattened similar neighborhoods in its path.

Another lesson learned from Charley was the number of residents who didn't know they lived in an evacuation zone. Officials throughout the region Friday discussed launching a new effort to advertise evacuation zones.

In Sarasota County, sheriff's deputies found themselves answering the same questions as thousands of evacuees driving over bridges from barrier islands slowed to ask where they could find a shelter.

To speed the exodus from future storms, Sarasota plans to give deputies pamphlets to distribute with directions, Sgt. Chuck Lesaltato said.

Even though Sarasota was spared the brunt of Charley, Lesaltato expects more cars coming over the bridges when the next storm approaches.

``I think people will respond after seeing the devastation that hit so close to home,'' he said.

Reporter Andy Reid can be reached at (813) 259-8409.