From The Conservative Woman

By Paul Homewood

MONMOUTH suffered some bad flooding last weekend as Storm Claudia passed through. Elsewhere only minor flooding seems to have occurred.

Rainfall storm totals over a day and a half were no higher than about 70mm in the region, which is not unusually high. Across the whole region of SW England and South Wales, where heavy rain was widespread, Met Office data shows 22mm for Friday, the day of the storm. But as the figures below show, days with 20mm or more happen regularly, about four times a year on average. It is abundantly clear that this sort of extreme rainfall is not on the increase, despite regular claims to the contrary.

One storm which particularly stands out took place in November 1931 when more than 50mm fell across the region. The Met Office Monthly Report at the time revealed just how serious the flooding was, not just in one locality but across much of the west of the country, including Cumbria:

Totals of 244mm at Trecastle make Claudia appear just another run-of-the-mill storm, which of course it was.

Rainfall was almost as bad in December 1960:

Seven inches is 178mm and 5.5 inches in the Rhondda in just 20 hours works out at 140mm.

Floods were widespread and serious in Glamorgan.

So why was flooding so bad in Monmouth this week in spite of much lower rainfall?

Grok has the answer:

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History of Flooding in Monmouth, Wales

Monmouth, located at the confluence of the Rivers Wye, Monnow, and Trothy in Monmouthshire, Wales, has a long history of flooding dating back centuries. The town’s position in a river valley makes it particularly vulnerable to riverine flooding from heavy rainfall, thunderstorms, and storms, often exacerbated by rapid snowmelt or overflow from tributaries like the Norton Brook. Historical records show events ranging from flash floods causing localised damage to widespread inundations affecting homes, businesses, and infrastructure. Below is a chronological summary of key flooding incidents in Monmouth before 2025, drawn from official reports and historical archives. This focuses on major events impacting the town itself, though Monmouthshire-wide context is noted where relevant.

9 June 1754

Severe hailstorm with stones up to six inches in diameter caused the River Monnow to overflow rapidly within an hour, depositing fish on streets. Damage to crops, windows, and homes in Monmouth and nearby Colford; widespread property destruction.

21 November 1766

Violent thunderstorm led to the River Wye rising several feet higher than previously recorded near Monmouth. Loss of lives and large quantities of goods; meadows and low-lying areas submerged.

20 June 1839

Intense thunderstorm caused the Rivers Wye and Monnow to overflow. Premises near Wye Bridge inundated; Monnow Street flooded to several feet deep.

2 April 1848

Prolonged thunderstorm with heavy hail and rain (over one hour 20 minutes) overwhelmed drainage. Many houses in central Monmouth flooded; streets turned into torrents.

31 May 1859

Heavy rains swelled the River Trothy, leading to overflow into Monmouth meadows. Walls washed away in nearby Skenfrith; houses drenched and stones carried downstream in Rockfield.

22 July 1907

Thunderstorm with marble-sized hail turned streets into rushing rivers. Significant flash flooding in town center; damage to gardens and minor structures (also severe in nearby Cwmyoy on River Monnow).

10 June 1912

Lightning storm during heavy rain implied widespread waterlogging. One man killed by lightning; roads and low areas flooded.

27 May 1931

Rapid rise of the River Monnow due to thunderstorms across Monmouthshire.
Floodwaters reached bedrooms in houses; Drybridge Street submerged to several feet (boats used for rescues); cattle and sheep washed away in The Forge district; worst flood in living memory at nearby Skenfrith; racecourse and military huts affected.

April 1947

Nationwide flooding event triggered by heavy snowfall followed by rapid thaw; Rivers Trothy and Monnow overflowed into Monmouth. Severe inundation in Drybridge Street (water to upper bedrooms, evacuations); widespread damage across town and upstream villages.

December 1979

Rivers Wye, Monnow, and Usk burst banks after prolonged heavy rain. Significant property flooding in lower Monmouth and Mayhill areas; multiple locations affected along riverbanks.

October 1998

Storm-driven rise in River Wye levels. Peak level of 17.19m AOD; homes and roads in low-lying areas flooded.

October 2000

Autumn storms caused River Wye overflow. Peak level of 17.59m AOD; internal flooding in several properties.

December 2000

Two separate events from winter storms. River Wye peaks at 17.58m and 17.61m AOD; over 50 residential properties reported flooded in Monmouth (including Blake Street and Wyesham).

February 2002

Multiple storms led to two floods.River Wye peaks at 17.59m and 17.6 m AOD (latter was previous record); extensive evacuations and damage in Mayhill and town centre.

July 2005

Summer deluge overwhelmed rivers. River Wye at 16.37 m AOD; localised flooding in meadows and streets.

January 2008
Winter storms caused moderate overflow. River Wye at 16.42 m AOD; some properties affected in lower town.

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As Grok points out, Monmouth has always been particularly vulnerable to flooding because it sits at the confluence of three rivers, the Wye, Monnow and Trothy. Its history is littered with floods every bit as bad as this week’s.

It might seem a daft place to build a town, but the Normans built the castle and town specifically because of those three rivers as the site allowed them to exert control over the river crossings. Since then Monmouth has continued to thrive because of its communication links.

Unsurprisingly the media tried to turn the storm into some sort of climate change-fuelled monster storm, with headlines of ‘a month’s worth of rainfall’. As we have seen though, such events are commonplace and have always occurred.

None of them bothered to actually check the facts and present the true story.

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Paul Homewood

Paul Homewood is a former accountant who blogs about climate change at Not a Lot of People Know That