The Environment Agency has warned that weather conditions in some parts of Britain could be the worst we've seen in years.
On Friday, coastal areas in western parts of the UK were hit with high tides and strong winds. But what's causing the bad weather?
Cold air from Arctic Canada has met warmer air from the south and the stronger the temperature contrast, the stronger the jet stream.
The jet stream is a band of air that travels around seven miles above ground. In winter, it's at its strongest when cold polar air meets warm tropical air.