residents will experience prolonged heavy rainfall, and that, according to abc 7's meteorologist mike nico, is more dangerous than heavy winds. >> rain that falls down for hours upon hours upon hours saturates the ground and then it runs off and that's where you get your flash flooding. just in the 12-hour time frame, hilo had 12 inches of rain, an inch of rain an hour. >> reporter: a study which appeared in the journal of nature found that hurricanes are hovering in one place for longer. in the past 70 years hurricane speeds have declined 10% worldwide. another study by the national hurricane center found that about 27% of all hurricane deaths in the u.s. from 1963 to 2012 were from rainfall flooding, where only 8% of the deaths, during that same time, were caused by strong winds. >> i'm hoping it changes course. but we can't assume that, and then have a major problem and say, well, we are hoping. so we're planning for the worst and hoping for the best. >> reporter: so, scientists say global warming is responsible for these hurricanes slowing down. now, the poles north and south are becom