Winds of more than 100mph disrupted transport, brought down power lines and damaged buildings as Storm Gertrude swept the country.
A rare red Met Office alert was in place for Orkney and Shetland earlier amid dangerously wild conditions in the Northern Isles on Friday.
Many other regions across the UK have yellow or amber warnings in place until Saturday for strong winds, heavy rain, snow and ice as the extreme weather continues to batter the country.
A gust of 105mph was recorded in Lerwick, Shetland, between 1pm and 2pm, and a similar speed was noted further north in Yell around an hour later, the Met Office confirmed.
Elsewhere, winds above 80mph battered Inverbervie in Aberdeenshire and Orlock Head in Northern Ireland. Large parts of the Scottish mainland saw speeds of over 60mph.
Winds reached 144mph in the Cairngorm mountains, and nacreous clouds, which the Met Office said are usually seen in polar regions, were also spotted in the north-east of Scotland.
Thousands of homes were left without power in Scotland and Northern Ireland.
The disruption in Scotland affected the Western Isles, Argyll, north west Highlands, Tayside, Aberdeenshire, Caithness and Shetland.
Scottish Hydro Electric Power Distribution (Shepd) had restored supply to more than 11,000 customers by early Friday evening, with fewer than 3,000 customers remaining to be re-connected.
In some areas flooding and road closures were hampering engineering teams, with strong winds and lightning grounding the helicopters used to carry out repairs and transport equipment.
Elsewhere, a man in Edinburgh was being treated in hospital after he was struck by flying debris in the Pinkhill area of the Scottish capital.
Flats were evacuated in Clydebank when scaffolding was blown through a roof.
And a number of people were injured on the A96 in Huntly, Aberdeenshire, when a lorry was blown over on to a car.
In Northern Ireland, it was a case of battening down the hutches after Storm Gertrude blew a pet rabbit up on to a roof in Omagh, Co Tyrone.
All schools in the Northern and Western Isles were closed with more following on the mainland throughout the day. Oxgangs Primary in Edinburgh was forced to close after part of a wall was blown off.
Even Prime Minister David Cameron was caught up in the disruption on his way to Belgium for EU talks.
Speaking on BBC Good Morning Scotland, he said: ''My first challenge is to get to Brussels as with hurricane (sic) Gertrude I've already had a flight problem so I'm racing across Scotland at the moment to get to Edinburgh Airport but I hope I will make it.''
Train and ferry services are also vastly reduced.
The latest front is expected to continue through the weekend.
The Scottish Environment Protection Agency (Sepa) has almost 40 flood warnings in place covering Ayrshire, Tayside, west central Scotland and the Highlands, while south of the border the Environment Agency is urging communities in southern England and parts of the North to stay alert to the risk of renewed flooding over the weekend.
The River Ouse in North Yorkshire and the Severn at Shrewsbury are expected to be particularly high.
Neil Davies, national flood duty manager at the Environment Agency, said: ''More wet weather this weekend means that communities in parts of southern England and the North should stay alert to the potential for further flooding.
''Teams from the Environment Agency will be out over the weekend continuing their work to check and repair flood defences as well as clearing watercourses and offering help and advice to communities still recovering from the impacts of flooding over Christmas.
''Strong winds combined with high tides could lead to large waves and spray especially for the Yorkshire coast and parts of southern and western coasts. We advise anyone near coastal paths and promenades to take extra care and to avoid the temptation to go 'wave watching'.''
P&O Ferries said the Pride of Hull ferry, from Rotterdam, had been unable to berth in the morning due to ''extreme weather conditions''.
A spokesman added the ferry had experienced winds of 60 knots, which he described as ''rare''.