Communities in south‑east Wales are waking to a cold, quieter Sunday after Storm Claudia’s deluge pushed Monmouth’s River Monnow to record levels, overtopping defences and swamping the town centre. With the low now slipping south, the Met Office says a much colder airmass will spread across the UK, bringing frosts and the risk of hill snow early in the week. Natural Resources Wales has confirmed the Monnow exceeded previous peaks set during Storm Dennis (2020) and last year’s Storm Bert, underscoring how saturated catchments can turn heavy rain into rapid, damaging floods.

Claudia’s rain was exceptional. Met Office data show 119.6mm fell at Tafalog in Gwent between Thursday evening and early Saturday-around two‑thirds of a typical November in just 12 hours-with additional amber warnings issued as bands of slow‑moving rain stalled over England and Wales on Friday. Winds touched 60–70mph in exposed spots, compounding the risk to power and transport.

Monmouth’s major incident-declared at 01:30 on Saturday as water surged through Monnow Street-was lifted on Sunday afternoon as levels fell and the clean‑up began. The priority now is supporting residents and traders back into homes and premises, restoring energy supplies and clearing debris from key routes. Local leaders have praised the swift work of fire crews, mountain rescue volunteers, council teams and neighbours who checked on older and vulnerable residents.

Travel has been hit well beyond the Wye valley. Great Western Railway services between London, Bristol and South Wales saw delays and diversions, with reports of flooding blocking the Swindon–Bristol Parkway corridor on Sunday morning. National Rail has urged passengers to check before travelling, while the AA advises drivers to avoid floodwater entirely-just 10cm can immobilise a car-until road conditions improve.

The immediate weather picture flips from sodden to sharp. High pressure to the northwest now draws Arctic air across the country, bringing daytime highs widely in the single figures (around 5–9°C) and a marked wind‑chill in brisk northerlies. Wintry showers are possible along northern and eastern coasts, with snow on higher ground in the northern half of the UK by Tuesday if pulses of moisture clip the cold air.

Why the switch? Through early November, a flatter jet stream kept the UK on its warmer, wetter side, feeding in mild maritime air from the south. As the pattern buckled negative‑NAO style in recent days, blocking near Greenland opened the door to colder northerlies. That shift also helped stall Friday’s rain bands over England and Wales, elevating flood risk as saturated ground struggled to drain.

For climate planners, the signals are familiar. A warmer atmosphere can hold about 7% more moisture per degree-fuel for heavier downpours-while UK studies project 5–15% more rainfall intensity per °C during extreme events. The State of the UK Climate report also shows wetter winter half‑years becoming more common, loading the dice for river and surface‑water flooding when storms like Claudia arrive.

If you live in a flood‑prone area, take today’s calmer window to reduce risk. Sign up for free flood warnings (England via the Environment Agency; Wales via Natural Resources Wales) and make a simple plan: where you’ll move vehicles, which items to lift, how to contact neighbours who may need help. If your home has flooded, ask your insurer about Flood Re’s Build Back Better scheme-participating policies can fund up to £10,000 of property flood‑resilience upgrades such as flood doors, raised electrics and water‑resistant floors during repairs.

Monmouthshire’s MP Catherine Fookes says the town will need to reassess defences after this weekend’s unprecedented water levels, a call echoed by residents across the Wye and Monnow catchments. Alongside engineered schemes, natural flood management-tree planting, leaky woody dams, reconnection of rivers to floodplains-can slow runoff and shave peaks. Government‑backed pilots show thousands of such measures can collectively store or slow over a million cubic metres upstream of at‑risk homes, while local partners like the Wye & Usk Foundation are already scaling this work in the Monnow and Wye.

Cold adds its own health risks. UKHSA has issued cold‑health alerts for the Midlands and northern England from Monday 17 to Friday 21 November; check on older neighbours, heat the rooms you use most to at least 18°C if you can, and watch for icy patches on untreated surfaces. For travel, stick with the basics: avoid driving through standing water, slow down in spray, and plan extra time while rail and road teams repair damage.