Flooding is expected and immediate action is required in part of Ilkley, the Environment Agency (EA) has warned.
A flood warning is in place on the River Wharfe at Denton Road, with experts warning of a worsening situation due to heavy rain.
In an update issued just before 11pm on Friday, the EA said: "This flood warning has been issued due to quickly rising river levels in response to rainfall on Friday.
"The current river level at Ilkley is 2.1m and is expected to peak at a level of 3.3m between 4am and 5am on Saturday. Areas of concern are properties around Denton Road, Middleton Avenue and the Cricket, Football and Rugby Grounds, the sewage works and Denton Bridge.
"Further bands of rainfall are expected over the coming days and river levels are expected to rise and fall."
A flood warning is also in place on the River Wharfe at Billams Hill and for riverside properties between Otley and Pool.
In an update at 10.35pm on Friday, the EA said: "The current river level at Otley is 1.1m and is expected to peak at a level of 1.8m at approximately 5am on Saturday."
Meanwhile, after an update at around 1am today ( Saturday), a flood alert remains in place on the River Aire.
An EA spokesman said: "Alert remains in force due to rainfall throughout Friday. Scattered showers are expected over the next 12 hours. River levels are expected to gradually fall through the early hours of Saturday morning but risk of flooding to low-lying roads and farmland remains. Areas most at risk are the Skipton Washlands, Snaygill Ings, and Cononley Washlands. Avoid driving on low-lying roads and keep clear of any footpaths which are close to watercourses."