Factors

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.