Grid distributor Elektrilevi says that, together with its partners, it had restored power to 11,500 households as of Thursday evening after eliminating 83 system failures, a job hampered by fallen trees and branches and other hazards.
"It has been difficult to get to the failure points because the roads are full of fallen trees," head of Elektrilevi's control center Jüri Klaassen said, via a press release.
"There have been cases during the work where a tree is removed from the line at the fault site, then a few moments later, another tree falls right next to it, severing the connection again," he went on.
Around 6,000 households were reported being without electricity Thursday afternoon, falling to 4,200 by 5 p.m., picking up again to over 7,300 shortly before 7 p.m., mostly on Saaremaa and in Harju County, falling again to 2,300 by 9 p.m.
Areas suffering the highest incidence of power failures also changed as the storm, which came from the northwest and left tens of thousands of households in Finland without electricity, moved across the country.
"The stronger wind in the afternoon has led to additional failures in many places, including the islands, where the storm started in the early morning hours. The first major failures can now also be seen in Lääne-Viru County, and it is feared that failures may also occur in Ida-Viru County in the late evening, because according to the forecast, the wind will start to rise there,"Elektrilev's Jüri Klaassen said Thursday evening.
Northern Saaremaa has also seen mobile phone connections interrupted due to damage to masts, though according to ETV news show "Aktutual kaamera" (AK) correspondent Margus Muld, speaking Thursday evening, the west of the island was hardest hit by Storm Alia, and in some cases households will be without power until Friday evening or even during the weekend.
Elektrilevi, which says its teams are working round the-clock, says it is giving priority to medium-voltage reconnections, so it is the low-voltage connections which will have to wait until the weekend to be restored.
Elektrilevi's outages heat map shows at the time of writing in excess of 3,300 power cuts nationwide, chiefly in northern Estonia, the western islands and also with a pocket of outages in the far southeast.
Elektrilevi stresses that downed power lines should on no circumstances be approached.
"If you notice a tree that has fallen on the line or any other dangerous situation, please call the failure hotline on 1343 or the emergency number, 112," the company says.
The storm is forecast to gradually blow out through the course of Friday.
Lääne-Viru County driver hospitalized following tree-strike
Fallen trees caused other hazards too. A person was injured in Tallinn Thursday morning by a fallen tree or tree branch, and another injury was sustained in Lääne-Viru County in the afternoon after a tree hit a truck driving Ridala-Nigula road in Vonnu village, injuring the driver.
The 42-year-old driver of the vehicle was injured and taken to hospital by ambulance after an emergency call was made shortly after 4.30 p.m., spokespeople for the Police and Border Guard Board's (PPA) western prefecture said.
The driver ended up in a ditch and had to be freed by first responders.
Sander Peremees, head of operations at the West Prefecture, urged people to avoid travel unless absolutely necessary, for as long as the storm continues.
The alarm center (Hairekeskus) said it had received 170 storm-related reports as of 4 p.m. Thursday, mostly regarding fallen trees on roads in the north and west of the country.
In one incident, solar panels had been blown off a roof in Kuressaare, capital of Saaremaa, ETV news show "Aktuaalne kaamera" reported.
Both Eckerö and Viking Line made ferry cancellations Thursday on the Tallinn-Helsinki routes, in Viking's case halting all journeys.
Tallink continued its operations.
Ferries between the mainland and Ruhnu, Vormsi, Manilaid, and between Saaremaa and Hiiumaa themselves also saw cancellations.
As the storm has gradually passed, ferry traffic between mainland Estonia and the islands is recovering.
On the Manilaid route, there may be disturbances in the departures of the passenger ferry Kihnu Virve from Munalaid at 11:15 a.m. and from Manilaid at 12:50 p.m. due to strong winds on Friday.
On the Ruhnu route, the departures of the passenger catamaran Runo from Ringsu at 7 a.m. and from Parnu at 4 p.m. have been postponed on Friday. Departures will take place on Saturday from Ringsu at 7 a.m. and from Parnu at 2 p.m.
On the Vormsi route, the departures of the passenger ferry Reet will take place according to schedule on Friday.
The ferry operating on the Rohukula-Heltermaa route started serving passengers again already on Thursday evening.
Editor: Andrew Whyte