The victim, aged in his 70s, was killed after the tree brought down power lines in the village of Bremhill, Wiltshire, yesterday.
Residents in many parts of the UK have been urged not to venture out.
Greater Manchester Police tweeted: "Severe weather warning - do not come into the city centre unless it's absolutely essential, due to strong winds."
More than 2000 military personnel were on "high-readiness" to respond to requests in flood-affected areas along the Thames Valley.
It came as the Prime Minister's spokesman said £5000 government grants for people to repair their properties hit by the floods in the southeast will not be means tested.
David Cameron's spokesman said the "repair and renew" payouts would not be affected by the location of properties in wealthy enclaves alongside the River Thames in Berkshire and Surrey.
It follows suggestions that taxpayers would be subsidising repairs to well-heeled home and business owners.
About 2.75 inches (70mm) of rain is forecast to fall by tomorrow in the West Country - more than the region would normally get in the whole of February - with south Wales, western Scotland, Northern Ireland and other parts of southern England also expected to bear the brunt of the deluge.