According to that map, orange waters are lapping the end of my garden. Went out to check this afternoon and found the valley to be very flooded but, fortunately, many vertical meters from me still.
Orange is "be aware".
Red is "crikey, it's wet".
That map covers watercourses, but not surface water flooding, which is pretty transient stuff. Most of the time you can ride through it though, if you take the crown...
Quite Orange is flood alert: rivers are expected to break their banks, flooding is possible of fields and low lying roads. possibily low lying isolated buildings.
Red if Flood Warning or Severe Flood Warning which implies flooding of properties is forecast.
ie orange, keep an eye on flood and weather forecasts, put high value paperwork in upstairs rooms.
Red find your sandbags, consider lifting furniture off the floor etc. pack your grab bags.
severe flood warning means too late, flooding that will pose a risk to life is expected time to leave.
