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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.