"Hindcast" model to make better predictions.

• Position: Hurricanes

Hurricanes are storms with maximum wind speeds in excess of 73 mph and are among the most damaging natural disasters in the U.S. The Atlantic hurricane season lasts from June 1 to Nov. 30. A conventional model can provide its forecast by the start of hurricane season, which allows people to prepare better. A University of Arizona, Tucson, team has developed a new model by using data from the 1950-2013 hurricane seasons. They tested the new model by seeing if it could "hindcast" the number of hurricanes that occurred each season from 1900-49.

Other investigators have estimated that damages from U.S. hurricanes from 1970-2002 cost $57,000,000, 000 in 2015 dollars--more than earthquakes and human-caused disasters combined for the time period.

Good forecasts of hurricane seasons have been around only since the early 1980s, says study coauthor Xubin Zeng, professor of atmospheric sciences. The historical average in the 20th century was six hurricanes per year. Until about the late 1990s, the existing models did a good job of predicting how many hurricanes would occur each year. However, in the 21st century, the number of hurricanes per season has become more variable, with 15 occurring in 2005, but only two in 2013.

Other forecasting models relied heavily on the state of the El Nino climate cycle, a...