A tropical cyclone is a rotating, organized system of clouds and thunderstorms that originates over tropical or subtropical waters and has a closed low-level circulation. Tropical cyclones rotate counterclockwise in the Northern Hemisphere.
A tropical cyclone with maximum sustained winds of 38 mph (33 knots) or less.
A tropical cyclone with maximum sustained winds of 39 to 73 mph (34 to 63 knots).
A tropical cyclone with maximum sustained winds of 74 mph (64 knots) or higher. In the western North Pacific, hurricanes are called typhoons; similar storms in the Indian Ocean and South Pacific Ocean are called cyclones.
A tropical cyclone with maximum sustained winds of 111 mph (96 knots) or higher, corresponding to a Category 3, 4 or 5 on the Saffir-Simpson Hurricane Wind Scale.
A system that no longer possesses sufficient tropical characteristics to be considered a tropical cyclone. Post-tropical cyclones can still bring heavy rain and high winds.
Saffir-Simpson Hurricane Wind Scale
Sustained winds of 74-95 MPH. Very dangerous winds will produce some damage. Well-constructed frame homes could have damage to roof, shingles, vinyl siding and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles likely will result in power outages that could last a few to several days.
Sustained winds of 96-110 MPH. Extremely dangerous winds will cause extensive damage. Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.
Sustained winds of 111-129 MPH. Devastating damage will occur. Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.
Sustained winds of 131-156 MPH. Catastrophic damage will occur: Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
Sustained winds greater than 156 MPH. Catastrophic damage will occur. A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.
Watches, Warnings, and Advisories.
Hurricane/Tropical Storm Watch
Hurricane/Tropical Storm conditions are possible within 48 hours.
Hurricane/Tropical Storm Warning
Hurricane/Tropical Storm conditions are expected within 36 hours
Exercise caution due to hazardous driving conditions. Be alert for ponding & debris on roadway; slippery roads and poor visibility.
Flooding is possible. Be Alert!
Flash Flood warning
Flooding is imminent or already occurring. Get to high ground if you are in a flood prone area.
Issued by Pacific Tsunami Warning Center (PTWC) after distant earthquakes with potential to create a tsunami in Hawaii. Tsunami waves are possible.
Issued whenever tsunami waves have been confirmed by the PTWC and/or a damaging wave is detected.
Urgent Local Tsunami Warning
Issued when a local earthquake has occurred and damaging waves are probable. Wave travel time may be as short as 10-20 minutes.