Frontal rain occur when: 2 air
masses reach. lighter, less dense,
warm air forced to rise over denser,
cold air. causes the warm air to cool
and condenses. As the warm air is
forced to rise further condensation
occurs and rain is formed.
Stationary front
over
Northumberland
80mm of rain fell
in 24
hours
Nature of surface
water & lateral flooding
Mitford Road
Inadequate draining
Road
surface
floods
Houses
flooded from
water from
street
Houses away
from river -
deeper flood
water
blocked by
houses -
Backing up
Central Morpeth
Oldgate bridge - Telford bridge
Flooding on
south side
confined to river
- steep ground
Streets flooded from
surface water -
blocked drains
Defensive walls
overtopped
High Stanners
Upper part of town
Abbey terrace flooded
Due to low level of road
& inadequate drainage
Reported flooding
from below floor
boards
Wansbeck and
Font showed that
56% of rain fall is
converted into
surface runoff
Hydrograph
Very intense
rainfall
Short period of time
decreased infiltration -
increased lag time -
increased peak
discharge