The Environment Agency has issued flood warnings for Hessle, Easington and Kilnsea, because of a combination of high tides and strong winds.
A lesser flood alert is in place for the bank of the Humber in Hull.
Properties at Hessle Foreshore will be at risk of flooding between 7pm and 10pm this evening (Friday).
The warning, which means "flooding is expected" covers the Waterside Business Park, Cliff Road, Saxon Way, the Buttfield Road area, and properties to the south of Hull Road.
Areas at particular risk include the Country Park Inn and the Country Park.
Staff at the Country Park Inn have been putting out sandbags.
A member of staff said: "We are just putting out sandbags as a precaution."
A Humber Rescue crew is on standby.
Dave Roberts, chairman of Humber Rescue, said: "We've got a full crew of 16 people on standby at our boathouse.
"We've got two small rescue boats and Landrover. Hopefully we won't have to use the boats.
"People should be aware that high tide will be the worst point of the flood tonight and that will occur at 8.42pm."
Mr Roberts warned that if flooding did occur, people should stay indoors.
He said: "People should stay indoors. Last time we had to save people who tried to drive through the water.
"We wouldn't want to see that happen again. The water came up so quickly It caught people unawares.
"The general advice I would give to people would be to stay indoors and listen to Radio Humberside."
However, a spokeswoman for the Environment Agency said any flooding was likely to be "overtopping", with waves coming over the sea wall. She did not expect any flooding on the scale of December 2013.
She said the tidal barrier in Hull was unlikely to be used tonight but could be used on Saturday.
A flood warning for the North Sea coast covers properties on the east side of Kilnsea, including Kilnsea Caravan Park, and Easington Caravan Park, between 6pm and 10pm tonight.
An Environment Agency statement reads: "High tide levels coupled with strong winds may cause overtoppping. The particular area at risk is Southfield Farm. Tide levels will remain high during the weekend."
Flood alerts, meaning "flooding is possible", have been issued for the Humber Estuary from Lords Clough to Hessle Haven – including the river frontage at Hull – from Hessle Haven to Faxfleet, from Spurn Point to Winestead Outfall, and for Withernsea, Easington and Kilnsea.
For updates, call Floodline on 0345 988 1188 or visit the Environment Agency website.Updated 6.30pm.
