Storm overflows spike to four times normal rate as thunderstorms hit England and Wales

Mason's ledger flagged 69 storm overflows discharging across England and Wales for the hour in question, against a baseline of 17 normally expected — roughly four times the typical rate. The reporting material does not give a direct cause-and-effect confirmation linking that overflow count to the specific storms described below, but the timing and geography line up closely with heavy rain and thunderstorm activity hitting the same region. Flooding struck part of the West Midlands on Wednesday night and into Thursday, with West Midlands Fire Service confirming it had been called to "significant flooding" in Birmingham after a flood warning was issued for the Perry Barr area owing to rising river levels, according to [1]. Crews worked alongside West Midlands Police and Birmingham City Council, and the public was advised to avoid the area where possible, according to [1]. Incidents were reported around Curbar Road, Thornbridge Avenue and Haddon Road, according to [1]. The Environment Agency had issued 22 flooding alerts across the Midlands and South East, according to [1]. The Met Office warned some areas could see 50–75mm of rainfall on Thursday alongside lightning and hail, with temperatures still reaching 27–28C, according to [1]. Met Office forecaster Craig Snell said the South East warning area could see 30–40mm of rain and hail up to 1–2cm, while the wider warning area could see more than 75mm over 12 hours in parts, according to [1]. A separate Met Office warning, reported in [2], had already put a yellow thunderstorm alert in force from 3am to 10pm on Wednesday 26 August, covering London, the South East, the Midlands, East Anglia, parts of the North West and South West, and large parts of Wales. The Met Office expected rainfall of 20–30mm in under an hour in places, with some locations seeing 40–50mm within two to three hours — rates capable of overwhelming drainage systems and producing surface water flooding, according to [2]. A further warning from 6am Thursday 27 August forecast another band of storms moving north, with up to 50mm possible over 12 hours in places, according to [2]. Both sources frame this as a sharp reversal after an extended dry spell: drought had been declared in nearly three-quarters of England and the whole of Wales following a summer of five heatwaves and temperatures up to 38.1C in London, according to [1]. The Met Office noted in [2] that the shift from heat and drought to intense downpours creates a "particularly difficult combination of conditions," since parched ground sheds water fast rather than absorbing it — a dynamic consistent with drains and sewer networks being pushed well beyond normal operating levels, as the overflow figures suggest. Neither source names storm overflow discharge data directly or confirms the 69-against-17 reading itself; that reading comes from the estate's own instrument. But the independent weather reporting in [1] and [2] — flood warnings, Environment Agency alerts, forecast rainfall of up to 75mm in 12 hours, and confirmed flooding incidents in Birmingham — gives a plausible and consistent backdrop for why overflow activity would be running at roughly four times normal for the hour flagged. What to watch next: whether the Environment Agency upgrades any of its 22 flooding alerts to warnings, and whether overflow counts fall back toward baseline once the Thursday evening storms clear north, as Met Office forecaster Craig Snell expects.