Cindy Minnix waits for a bus in a flooded street. Published reports indicate that Florida ranks as the most vulnerable state to sea-level rise, with some 2.4 million people, 1.3 million homes and 107 cities at risk from a four-foot rise in sea levels. - 

Today, there are about the highest tides of the year in South Florida.

And in a low lying area like that, a really high tide is more of a problem that you might otherwise think. The 3.59 foot high tide this morning at 8:30 a.m. caused flooding in many areas.

It's a warning, as well, of what to expect as sea levels keep rising.

In Ft. Lauderdale, the water came over a low sea wall and onto Mola Street, where Judy Mudge has lived for 20 years. "An hour ago it was almost to the door here," Mudge says, "almost to the back door."

She doubts it's because of climate change since her street always floods seasonally, but gauges show the ocean around here has gained about nine inches in the last hundred years, and many experts think it's accelerating.

South Florida is low, flat, already wet and bound to get wetter. A European study finds Miami is the single most ocean threatened city in the world. The U.S. Army Corps of Engineers says sea level here could go up seven-inches by 2030.

At the intersection of 10th and Alton in Miami Beach, a mix of sea water and sewage is almost knee-deep. Underground pipelines meant to drain storm water to the ocean are carrying the ocean here.

Charmain Howell was on a bicycle, the water up to her wheel hubs. She moved away from here, she says, but is back visiting -- and happened to run into what's called a king tide.

"'I was just trying to go to Walgreen's," Howell says. "I'm thinking, 'forget about it, it's not worth it.' It's like ridiculous. This is the worst I've seen it. It's been bad, but this is the worst, for sure."

Regional planning groups have ideas for adapting to high levels of sea here, but sea level projections for 40 and 50 years out are so serious -- two feet higher, maybe more -- adaptation may not work.

For people that want to be able to get to the drug store and in places in South Florida, that may not be possible.

Alex Chadwick is the host of BURN: An Energy Journalfrom SoundVision Productions and American Public Media