Factors Affecting Height And Time Of The Bore

(in addition to height and time of high water at Sharpness)

Bore height INCREASED by

i. Strong west to south-west winds
ii. About 0.75 metres of freshwater below Gloucester
iii. Channels of estuary well scoured
iv. Low barometer

Bore height DECREASED by

i. Strong north to east winds
ii. Absence of freshwater
iii. Too much freshwater
iv. High barometer

Bore made EARLIER by

i. Strong west to south-west winds
ii. Up to 15 metres of freshwater
iii. Channels cutting shorter routes through estuary sands
iv. Channels well scoured
v. Low barometer

Bore made LATER by

i. Strong north to east winds
ii. Absence of freshwater
iii. Channels cutting longer routes through estuary sands
iv. Channels unscoured, with high beds
v. High barometer

Note: The strength and direction of the wind out at sea is often of more consequence than prevailing local wind conditions.