![\"A](\"https:\/\/images.newscientist.com\/wp-content\/uploads\/2024\/10\/09201637\/SEI_225048271.jpg\")
<\/div>Commuters on Interstate 75 driving away from Florida\u2019s west coast ahead of the arrival of Hurricane Milton<\/p>\n
Marco Bello \/ Reuters<\/p>\n<\/div>\n<\/figcaption><\/figure>\n<\/p>\n
Hurricane Milton has spawned at least two large tornadoes ahead of making landfall on Florida\u2019s west coast later tonight, and a tornado watch has been issued for much of the southern part of the state.<\/p>\n
Such tornadoes are not uncommon \u2013 they are observed in more than 80 per cent of hurricanes<\/a> that made landfall in the Gulf Coast \u2013 but it is unusual for them to be so clearly visible ahead of the hurricane, says William Gallus<\/a> at Iowa State University. \u201cThere have been a surprisingly large number already and they look like Great Plains tornadoes,\u201d he says. \u201cThey\u2019re wide.\u201d<\/p>\n There are two main ingredients needed for hurricanes to spawn tornadoes, which add to the destructive potential of a storm. The first is instability created by heat and humidity in the atmosphere. The second is differences in wind speed and direction at different altitudes, known as wind shear.<\/p>\n Hurricanes moving over water normally have relatively low wind shear because there isn\u2019t much friction between the storm and the sea surface. \u201cIt is like this giant spinning cylinder, so the winds aren\u2019t very different on the ground than they are up high,\u201d says Gallus.<\/p>\n <\/p>\n That changes as the storm makes landfall, and friction with the ground slows winds at lower altitudes, which also drives them towards the centre of the storm. When the air is hot and humid enough, these intense winds can form tornadoes.<\/p>\n \n