BANGKOK, Thailand -- A cyclone with winds up to 120 mph. A low-lying, densely populated delta region, stripped of its protective trees.

When Cyclone Nargis struck Myanmar's Irrawaddy delta and pushed a wall of water 25 miles inland, it had all the makings of a massive disaster.

"When we saw the [storm] track, I said, 'Uh oh, this is not going to be good,'" said Mark Lander, a meteorology professor at the University of Guam. "It would create a big storm surge. It was like Katrina going into New Orleans."

Forecasters began tracking the cyclone April 28 as it headed toward India. As projected, it took a sharp turn eastward but didn't follow the typical cyclone track in that area leading to Bangladesh or Myanmar's mountainous northwest.

Instead, it swept into the low-lying Irrawaddy delta.

It was the first time such an intense storm hit the delta, said Jeff Masters, co-founder and director of meteorology at the San Francisco-based Weather Underground. He called it "one of those once-in-every-500-years kind of things."

"The easterly component of the path is unusual," Masters said. "It tracked right over the most vulnerable part of the country, where most of the people live."

When the storm made landfall early Saturday at the mouth of the Irrawaddy River, its battering winds pushed a wall of water as high as 12 feet some 25 miles inland, laying waste to villages and killing tens of thousands sleeping in the region's flimsy shacks barely above sea level. Almost 95 percent of the houses and other buildings in seven townships were destroyed, Myanmar's government says. U.N. officials estimate 1.5 million people were left in severe straits.

The delta had lost most of its mangrove forests along the coast to shrimp farms and rice paddies during the past decade. That removed what scientists say is one of nature's best defenses against violent storms.

"If you look at the path . . . much of the protective vegetation was cleared," said Jeff NcNeely, chief scientist for the International Union for Conservation of Nature.

"It's an expensive lesson, but it has been one taught repeatedly," he said. "You just wonder why governments don't get on this."

Some environmentalists suggested global warming may have played a role. But most weather experts are divided over whether global warming is a factor in catastrophic storms.