Storm Doris has become a "weather bomb" as it batters Britain according to forecasters from the Met Office.
The storm swept in across the west of the UK on Thursday morning, bringing with it heavy rain and wind gusts of up to 80mph.
Flights have been cancelled at Manchester Airport, trains delayed on the line to Liverpool and filming has been cancelled on the set of Coronation Street.
But what is a weather bomb?
While it may sound like a term dreamed up by tabloid headline writers, there is actually a way for meteorologists to measure it.
According to forecasters, the storm "rapidly deepened" this morning and underwent "explosive cyclogenisis".
This process happens when dry air flows quickly into an area of low pressure. It creates a more vigorous storm, or weather bomb, as the air within the depression rises very rapidly, increases its rotation and intensifies the pressure.
Meteorologists say to be classed as a weather bomb, the central pressure of the storm system must dip by 24 millibars in a 24-hour period.
Storm Doris has fulfilled this criteria, meaning it is now a weather bomb.
It may explain why the storm has caused so much disruption, including a blocked railway line at Liverpool Lime Street which means there is severe disruption between Manchester and Liverpool. A number of flights have been cancelled including to the Isle of Man and Amsterdam.
Passengers whose flights are cancelled are being advised to take advice about getting their money back.