Tomorrow sees one of the highest tides of the year forecast for King's Lynn, meaning a tidal wave is possible inland.
The Environment Agency is predicting high water in the River Ouse will peak at 4.7m at around 8am on Monday, September 30. Similar levels are expected on Tuesday, when high water is expected at 8.42am.
The spring tides - as they are called despite the time of year being anything but - bring one of the region's great natural phenomena to the Ouse, in the shape of the Wiggenhall Wave.
This is a tidal wave or bore, more than 1m high, which forms where the river narrows upstream of Lynn when the flood tide begins.
It rushes inland at around eight knots, attracting swimmers, surfers and kayakers to ride on it.
Wave watcher Kevin Holland, who runs a green energy business beside the river at Magdalen, said the wave would occur around 7.30pm on Monday.
An Environment Agency spokesman said: "High tides are predicted for Monday, Tuesday and Wednesday of next week. We are currently monitoring the situation and talking to partner organisations in Kings Lynn.
"The level of the tide depends on a number of factors including wind direction and pressure systems. By Sunday we will have a more accurate tidal forecast and will know whether flood alerts need to be issued and the necessary flood gates closed."
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