Thousands of homes were left without power, properties were damaged and there was widespread travel disruption as Storm Francis battered Wales.
Falling trees damaged homes and vehicles and blocked roads across Wales after a "danger to life" wind warning.
Nine people were rescued after a campsite flooded and six people had to be rescued from a flooded property.
River searches in Cardiff were suspended after reports of people in the water.
A weather warning for wind covered most of Wales until 09:00 BST on Wednesday, with gusts of 75mph (120km/h) recorded at Lake Vyrnwy, Powys, according to BBC Wales forecaster Derek Brockway.
The Met Office had warned of a "danger to life" due to flying debris and large waves, with the possibility of homes, buildings and roads being damaged in the storm.
In north Wales, firefighters had to help six people to safety after a property became flooded at Abergwyngregyn, in Gwynedd.
Footage shared on Twitter showed a torrent of water passing homes.
Mam newydd anfon hwn - wrth y ddistyllfa a’r hen dafarn yng ngwaelod Abergwyngregyn.— Elin Roberts (@Elin_A_Roberts) August 25, 2020
Residents being evacuated near the Aber Falls distillery. Never seen it this bad. #llifogydd #StormFrancis pic.twitter.com/vpa0ry2QBU
A number of properties and businesses in Cardiff were damaged as trees fell down in high winds.
South Wales Police said Church Street in the city centre had been "evacuated and will remain closed for several hours" due to damage caused to buildings by strong winds.
Earlier on in the capital, a man was inside his restaurant when a tree crashed through the roof.
Mamun Miah said he was making phone calls in the newly refurbished Lake Spice restaurant when the wind picked up.
"I saw the building start shaking and the whole tree fell down and the double doors smashed completely," he said, adding that no-one was hurt."I had two colleagues in the kitchen who started running out, they saw something had happened and saw the whole roof come down."
Scottish Power said 3,000 of its customers in Gwynedd and Powys had been without power due to high winds.
Western Power Distribution said its teams attended dozens of incidents which had left homes without electricity in Powys, Swansea, Carmarthenshire, Neath Port Talbot and Caerphilly county.
It said about 9,000 properties lost power on Tuesday evening across south Wales, south west England, and the Midlands.
Around Cardiff, trees came down in Colchester Avenue and Boverton Street, Pen y Lan, Plasturton Gardens, Pontcanna, St Fagans Road in Fairwater, Heol Uchaf in Rhiwbina, and on Windsor Road, Penarth, in Vale of Glamorgan.
In north Wales, the A55 was hit by flood water and fallen trees blocked roads near the A55 at Holywell and the A548 near Bagillt, both in Flintshire, and Mold Road in Wrexham.
The A5 between Nant Ffrancon and Capel Curig in Snowdonia was closed due to a landslide, and the A55 at Llanfairfechan, Conwy county, was blocked due to flooding.
Dyfed Powys Police said officers had been dealing with a "high volume of trees and lines down" around Brecon, and Gwent Police said a tree had blocked St Brides Road, near the M4 bridge at Magor.
Earlier on Tuesday, the A4076 at Hamilton Terrace, Milford Haven was blocked by a fallen tree, while another was partially blocking the road between Clarey and Star.
In Gwynedd, a tree branch came down across the A494 between Bala and Dolgellau.
The M48 Severn Bridge was closed in both directions and traffic was diverted across the M4 Prince of Wales bridge.
Elsewhere, fallen trees closed the A487 near the Dyfi Bridge in Gwynedd, the A4080 on Anglesey, the A4160 in Vale of Glamorgan, the A470 in Conwy, the A4042 in Torfaen, and the A4119 in Cardiff.
💨#StormFrancis 17:00 Update— Trafnidiaeth Cymru Trenau Transport for Wales Rail (@tfwrail) August 25, 2020
Due to a tree blocking the railway between Bridgend and Cardiff Central the line towards Cardiff is blocked.
Services running through these stations may be cancelled, delayed by up to 60 mins or diverted via Rhoose. Disruption expected until 17:45. pic.twitter.com/lcRlJytVBz
Rail services have were also heavily disrupted across the country, according to Transport for Wales.
A tree was blocking the line between Cardiff Central and Bridgend, and a number of services were cancelled, including between Llandudno Junction and Blaenau Ffestiniog, Ystrad Mynach and Heath High Level, Cross Keys and Ebbw Vale Town, Shrewsbury and Crewe, and Carmarthen and Swansea.
Flooding also closed the line between Craven Arms and Llandrindod, with replacement services in place from Wednesday.
Earlier on Tuesday, campers enjoying the last of their summer holiday were rescued across parts of south Wales after the flood waters rose.
Firefighters used lines and wading gear to rescue nine people and two dogs from a flooded campsite in St Clears, Carmarthenshire, after river levels rose.
The owner of Lakeside Leisure Campsite said everyone was safe and was now in alternative accommodation following the incident.
It had only been open a month following coronavirus restrictions.
Bradley, who did not give his last name, said: "They are all fine, they're drying off.
"We couldn't have foreseen it, it was just the rainwater running down from the hills.
"This year has been dreadful, we've been able to open for a month and it has just poured down."
Natural Resources Wales said the levels at the River Cynin were 2m above their normal levels.
Campers at Llwyngwair Manor Holiday Park, in Newport, Pembrokeshire, woke to a "frightening" scene, its manager said.
"Within a very short period of time the river was swollen and it was time to wake the visitors," said Meleri Clare Ennis.
"Everything happened so quickly and I hope we're over the worst."
A yellow weather warning for rain was in place for counties in mid and north Wales until 06:00 on Wednesday.
A number of properties flooded in Neath, Whitland, Tonyrefail and Llanelli, while roads were closed and some trains disrupted after part of the south Wales main-line railway was left underwater.
National Rail tweeted that the railway line at Neath had been blocked, with trains between Swansea and Cardiff cancelled or delayed.
A 30mph speed limit was in place on a number of services in south Wales, with passengers warned to expect delays due to the severe weather.
Traffic Wales warned of "extremely poor driving conditions" and said people should plan ahead.
There were flood warnings in place along rivers in Carmarthenshire, with communities told to be prepared. There were also a number of flood alerts in place.
Chepstow Racecourse said it had cancelled its scheduled races on Wednesday due to the heavy rain.
Swim Wales warned people not to take "unnecessary risks" at the coast as "large waves can easily pull you out to sea".
Please also note to avoid any rivers as the Taff and Ely are in full spate after the previous night's rainfall - we have already had incidents in the #Cardiff area including a person rescued after going in after their dog, and a capsized canoe. #BeCareful #StaySafe #WeatherAware https://t.co/3MZkKDSp4P— EVAC Cardiff (@evaccardiff) August 25, 2020
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