( CNN ) -- Days of heavy rain have led to flooding in southwestern England and parts of Wales and at least one fatality , British authorities said Sunday . The UK Environment Agency posted a severe flood alert for the town of Helston , in the southwestern county of Cornwall , where the River Cober was rising over its banks , and warned towns across England and Wales to prepare for more high water . In Exeter , in neighboring Devon , a woman was killed when a tree fell on her Saturday night , the Devon and Cornwall Police Service reported . The Environment Agency said more than 800 properties have flooded since Wednesday . And the Met Office , the UK 's national weather service , said more rain is forecast for the area -- but the wettest weather will be in the north . `` We can expect between 30 and 40 millimeters ( 1 1/4 to 1 1/2 inches ) of rain falling in many areas and up to 70 millimeters ( 2 3/4 inches ) of rain in parts of northeast England , continuing the risk of further flooding and travel disruption , '' forecaster Eddy Carroll said in a news release . On Twitter , Prime Minister David Cameron called the scenes of flooding `` shocking '' and said his government would make sure `` everything is being done to help . '' The region has seen four days of non-stop rainfall that has capped months of heavy precipitation , including the wettest April-June period on record . More than 225 areas stretching from Cornwall through the Midlands region to the northeastern coast were under flood warnings Sunday afternoon as the latest system moved through , the Environment Agency said . Officials warned residents to use the daylight to prepare for more flooding Sunday and into the early hours of Monday . CNN 's Susannah Palk and Matt Smith contributed to this report .
NEW : More rain , flooding forecast for days . Flood alerts posted across Wales and England after Sunday of rain . A falling tree kills a woman in southwestern England . the Met Office pledges help for the stricken region .