ST. PETERSBURG, Fla. (AP) -- Hurricane Irma became tied for the seventh strongest storm to make landfall in U.S. history by a key measurement of atmospheric pressure.
Hurricane Irma made landfall at Cudjoe Key at 9:10 a.m. with a minimum central pressure of 929 millibars. Atmospheric pressure is one of the major measurements meteorologists use to describe storms. The lower the pressure, the stronger the storm.
Only six storms on record had lower pressures when striking the United States, including Katrina. When Katrina hit in 2005, it had lower pressure but its wind speed kept it at Category 3.
The 929 pressure mark ties Irma with the deadly 1928 Lake Okeechobee hurricane.
Irma's arrival also marks another first.
Colorado State University hurricane researcher Phil Klotzbach says this is the first year on record that the United States has been hit by two storms that were Category 4 upon landfall: Harvey and Irma.
Meanwhile, Florida utility officials say more than 1 million customers have lost power as Hurricane Irma hits the state.
Florida Power & Light Company said that nearly 1.1 million customers statewide were without power Sunday morning.
About 574,000 of those outages were in Miami-Dade County, while there were 360,000 in Broward and nearly 136,000 in Palm Beach County.
The massive storm made landfall in the Florida Keys, and its center was forecast to move up the state's Gulf Coast. But the effects are being felt far from the center because of Irma's size.