The Bureau of Meteorology is warning a storm system with the potential to be the strongest cyclone of the season is set to hit Western Australia's northovernight.
A system moving over the Kimberley coast today is expected to develop into a category three or above tropical cyclone on Friday or Saturday, bringing huge amounts of rain to the already saturated region.
A blue alert has been issued for people between Kuri Bay and Wallal, with a cyclone watch issued for those between Kuri Bay and Whim Creek.
The bureau said there would be widespread flooding, with up to 200 millimetres of rain forecast to fall over the West Kimberley in the next few days, and isolated totals of up to 400mm.
Flooding is set to be most severe along the North, West and East Kimberley Rivers and the Fitzroy River.
If the system does develop, it will be called Tropical Cyclone Kelvin and will be the fifth of the cyclone season in WA's jurisdiction and the third to hit the state's coast.
The Department of Fire and Emergency Services has urged people in the Kimberley to stock up on supplies now.
Rain, flash-flooding warnings
The warning comes after an area of the Kimberley larger than Victoria was earlier this month isolated by flooding, following after a severe storm that dumped nearly 640mm of rain in four days.
Large sections of the Great Northern Highway and the road between Broome and Derby were swept away by floodwaters and are still under repair.
The Kimberley, Inland Pilbara and Southern Gascoyne regions also experienced heavy rains in mid-January as a result of ex-Tropical Cyclone Joyce along with winds of up to 126 kilometres per hour in the state's south.
DFES spokesman Glenn Hall said even if the new system does not form into a tropical cyclone, it is still expected to bring a significant amount of rain to areas that have already had plenty over the past few weeks.
"This predicted rainfall could cause further damage to the road network which has already been impacted by the storms", Mr Hall said.
"Flash flooding is expected over already damaged routes."
Mr Hall urged people in towns across the West Kimberley, including Broome and Derby, to prepare now before it is too late.
"Fill up your car, as well as making sure you've got enough non-perishable food items to last any potential isolation we may have because the road is affected by flooding", Mr Hall said.
"We recommend at least three days worth of food for each family member as a minimum."
Mr Hall said if people really needed to travel, they should keep up to date with weather warnings and check travel routes on the Main Roads website before setting off.
"It's also worthwhile preparing an emergency kit, and remember to look after any medications you might require, as well as your pets," Mr Hall said.ABC