In dangerous company

Hurricane Harvey was upgraded to a Category 4 storm as it approached the Texas Gulf Coast overnight. It’s the biggest storm to hit the U.S. since Hurricane Wilma devastated cities and towns in southern Florida in 2005. Hurricanes are labeled based on the Saffir-Simpson Hurricane Wind Scale, which measures sustained wind speeds.

CATEGORY 1

— Wind speeds between 74 and 95 mph; can damage roof shingles and vinyl siding, down tree branches, topple shallowly rooted trees and damage power lines. In August 2016, Hurricane Hermine was a Cat 1 storm when it made landfall in Florida.

CATEGORY 2

— Winds between 96 and 110 mph; can cause significant roof and siding damage, snap and uproot trees and create widespread power outages. Hurricane Arthur, the first named hurricane of 2014, was a Cat 2 storm when it hit North Carolina.

CATEGORY 3

— Winds between 111 and 129 mph; can cause major damage to houses and even remove roof decking, tear well-rooted trees from the ground and leave communities without water or electricity for weeks. Hurricane Sandy, which caused $75 billion in damage in 2012, was a Cat 3 storm when it hit Cuba and weakened as it approached the U.S.

CATEGORY 4

— Winds between 130 and 156 mph; can cause catastrophic damage; even well-built homes can lose most of their roofs and some exterior walls; most trees and power lines will be knocked down and power outages could last months. Hurricane Dennis was a Cat 4 storm when it hit Cuba in 2005.

CATEGORY 5

— Winds greater than 157 mph; huge devastation. Hurricane Katrina, the costliest natural disaster in U.S. history, strengthened to a Cat 5 storm over the Gulf of Mexico and was a Cat 3 when it hit southeast Louisiana.