A severe storm, predicted to be the worst in 36 years, has hit Guernsey with more strong winds expected.
Winds of up to 85mph (136km/h) are expected as Storm Ciarán hits the Channel Islands from Wednesday evening into Thursday afternoon.
Meteorologists have confirmed it is a weather bomb, due to the explosive power of storms caused by a particularly rapid fall in pressure.
Schools and Guernsey and Alderney airports will close on Thursday.
Significant disruption is expected to roads, ferry services have been cancelled and people have been warned to stay at home, to keep their pets indoors and to only travel if essential.
'Stay at home'
Home Affairs Committee President Rob Prow said: "The effort and preparations across the States gives me confidence that the community will be kept as safe as possible, but I would agree with the advice from the chief of police and others for islanders to stay at home wherever possible.
"By looking after yourselves and keeping safe, you allow our services to focus on tackling issues resulting from the storm.
"We are hugely fortunate to have such dedicated personnel working in policing, the fire and rescue service, the ambulance service, civil protection and more all with the aim of keeping the island and its people safe and secure."
Nick Hynes, director of education, said the "paramount priority" was the safety of staff and children when deciding to close schools.
He said: "Taking that decision and ensuring we can make sure that they're all safe, we've taken the decision that it's best just on Thursday that we close all school settings and Guernsey Institute."
Guernsey Post confirmed it would not be doing any deliveries or collections on Thursday, and post offices would be closed.
Analysis: Robert Hall, Jersey
A lot of people in the islands, like in the UK, remember the Great Storm of 1987.
Local forecasters are saying right across the Channel Islands that this could be as bad as that, and that's very dangerous for people who live here.
If you imagine Storm Ciarán as an arrow coming up the English Channel, the Channel Islands are right in the middle of the head of that arrow, with the strongest winds at least 90mph (144km/h), possibly up to 98mph (158 km/h) gusts.
And, if you couple that with a 30ft (9m) swell on the incoming tide, it's like a perfect combination of events; the wind, the tide and the morning rush hour.
A weather bomb, or explosive cyclogenesis, is a term given by meteorologists to a storm that appears to intensify rapidly, with its central air pressure dropping at least 24 millibars (mb) in 24 hours.
Storm Ciarán is expected to see a pressure drop of 28mb in 24 hours, from 06:00 GMT on Wednesday to 06:00 on Thursday.
Harbour authorities and the Guernsey Boatowners Association had advised boat owners to check their vessels, and those moored nearby, ahead of the storm.
Many shelves in supermarkets across the island were emptied ahead of the storm, as islanders stockpiled in case the weather disrupts the supply chain.
SandpiperCI will close all its Guernsey food stores at 19:00 on Wednesday.
Morrisons, Iceland and Checkers Xpress stores plan to open on Thursday at 12:00 but times will remain under review.
All branches of HSBC, NatWest and Barclays banks are closing.
The GSPCA said islanders should consider their safety before putting themselves at-risk rescuing animals.
Manager Steve Byrne said: "There is likely going to be a lot of casualties over the coming days from the extreme weather from marine mammals; seals are currently having their pups, through to those hedgehogs who are going to struggle finding their food.
"We want to highlight people's safety comes first, but we're at the end of the phone for advice."
The States of Alderney also advised islanders to stay at home and to not travel unless it is essential, and that St Anne's School and pre-school would be closed.
The eastern section of Rue de Beaumont will be closed on Thursday, as will St Anne's Church Car Park.
Sandbags have been made available from States Works to homes that are prone to flooding.
The States of Alderney said Commercial Quay was closed on Tuesday to members of the public and that it would reopen once "conditions moderate".