A powerful storm churned over America Calm lashed the area of Guam and the island with wind and rain.
Typhoon Mawr is the most powerful hurricane to affect a US area of about 150,000 people since 2002. The storm briefly made landfall on Wednesday night as a Category 4 hurricane at Andersen Air Force Base on the northern tip of the island.
Follow our live blog for all the latest updates
Some commonly used meteorological terms and their definitions, based on content from the National Weather Service:
Atmospheric River – Long and wide plumes of moisture that form over the ocean and flow from the sky over land.
Blizzard – Falling and/or blowing snow with wind speeds of 35 mph (56 kph) or more and visibility less than one-quarter mile (0.40 km) for three or more hours.
Cyclone – A storm with strong winds rotating around a moving center of low atmospheric pressure. The term is sometimes used to mean tornado in the United States and hurricane in the Indian Ocean region.
Derecho – A widespread and usually fast-moving straight-line thunderstorm. It is typically more than hundreds of miles long and more than 100 miles (161 km) wide.
BoyLa Nina – El Nino is a naturally occurring climate phenomenon that begins with unusually warm waters in the central and eastern equatorial Pacific and then changes weather around the world. The flip side of El Niño is La Niña, a temporary but natural cooling of the equatorial Pacific that also changes weather around the world.
Hurricane or Typhoon – A warm-core tropical cyclone with minimum sustained surface winds of 74 mph (119 kph) or higher. Hurricanes originate east of the International Date Line. Typhoons develop west of the line. They are known as cyclones in the Indian Ocean and in Australia.
Microburst – Occurs when a body of cold air races downwind of a thunderstorm, hits the ground and rushes outward in all directions.
polar vortex – usually refers to the giant circular upper air weather pattern in the Arctic region that surrounds it North Pole (But this may also apply to the South Pole). This is a general pattern that is stronger in winter and keeps some of the coldest weather bottled up near the North Pole. The jet stream usually pushes the polar vortex inwards and keeps it facing north. But at times some vortices can break or move south, bringing unusually cold weather to the south and allowing warm weather to creep in to the north.
Avalanche – An intense but short-lived period of moderate to heavy snowfall with strong winds and possible lightning.
Storm Surge – An abnormal rise of water above the normal tide produced by a storm.
Super typhoon – a storm with maximum sustained surface winds of 150 mph (241 kph) or greater.
Tornado – A violently rotating column of air, usually from a cumulonimbus cloud, and touches the ground, forming a pendent. On a local scale, it is the most destructive of all atmospheric phenomena. Tornadoes can appear from any direction, but most in the US move from southwest to northeast. They are measured on an F-scale from EF0 to EF5, which considers 28 different types of damage to structures and trees. An EF2 or higher is considered a significant tornado.
storm warning national weather service Issues with warning the public about an existing tornado.
Tornado Watch – Alerts the public to the possibility of a tornado forming.
tropical depression – a tropical cyclone with maximum sustained surface winds of 38 mph (61 kph) or less.
tropical storm – a warm-core tropical cyclone with maximum sustained surface winds of 39 mph (63 kph) to 73 mph (117 kph).
Tsunami – A large sea wave or seismic sea wave caused by an underwater disturbance such as an earthquake, landslide or volcano.
Nor’easter – The term used by the National Weather Service for storms that either break out or move north along the East Coast, with winds blowing from the northeast.
Waterspout – Tornado over the water.
Wind Chill Factor – A calculation that describes the combined effect of wind and cold temperatures on exposed skin.
Wind shear – a sudden change in wind direction and/or speed.