Storm Dennis has exploded into a bomb cyclone as meteorologists dub it one of the worst North Atlantic storms ever recorded.
This will come as a second blow to flood-ravaged communities still recovering from damage caused by heavy rainfall and 80mph winds brought by Storm Ciara last week.
Last week's storm - likely the biggest in the century - claimed three victims after a falling tree killed a 58-year-old Mercedes driver, a 77-year-old man fell over and banged his head on ice and a falling branch killed a dog walker in his sixties.
And now, 1,200-mile wide 'Dennis the Menace' - which will bring 60mph winds and 100mm of rain in some areas - is to cause mayhem for towns in Yorkshire's Calder Valley, which was inundated with floodwater when Storm Ciara raged.
Storm Dennis has exploded into a bomb cyclone as meteorologists dub it one of the worst North Atlantic storms ever recorded. Yesterday in Mytholmroyd, West Yorkshire, officials were seen desperately trying to prepare for Storm Dennis by using sandbags as flood defences
Workers in the Calder Valley towns of West Yorkshire (pictured today) are already trying to recover from the devastating effects of Storm Ciara, but are using sandbags to prevent further damage to the area with Storm Dennis looming tomorrow
The 1,200-mile wide storm will bring mayhem for towns in Yorkshire's Calder Valley, which was inundated with floodwater on Sunday
Local authorities are quickly trying to construct flood defences so the Calder Valley towns of Mytholmroyd and Sowerby Bridge don't suffer any further flood damage
A 'bomb cyclone' – also known as explosive cyclogenesis or a weather bomb – is caused by a steep drop in air pressure within a storm.
It usually creates winds of 74-95mph.
For a bomb cyclone to begin, air pressure must drop by 24 millibars within 24 hours - which means a rapid shift from good weather to bad.
The phenomenon got its name due to the dramatic drop in pressure being similar to a bomb exploding.
The Environmental Agency have warned that due to the water-soaked ground left over by Storm Ciara, the latest flooding is expected to be worse what has been seen so far, the BBC reports.
Storm Dennis became a 'bomb cyclone' on Thursday, when air pressure dropped by 24 millibars within 24 hours.
Remarkably, this is over two times the drop necessary to give the phenomenon its extreme name.
Met Office meteorologist Greg Dewhurst told Glasgow Live: 'On a slightly more technical definition, it's called rapid cyclogenesis. It's a low pressure system which drops 24 milibars in 24 hours or more.
'An easier way to think of it is, it's a low pressure weather system that drops really quickly.'
While Iceland, will feel the brunt of the storm - that could potentially be one of the worst North Atlantic storms on record - the UK will be lashed by high