(Adds details of road closure, quotes)
By Steve Quinn
JUNEAU, Alaska, Jan 27 (Reuters) - Road traffic to Valdez, Alaska, was cut off from the rest of the state after a series of avalanches over the weekend blocked the only road into the coastal community, officials said on Monday.
The highway to the town of about 4,000 was blocked after an avalanche in the Keystone Canyon on Friday, followed by another on Saturday, Alaska Department of Transportation and Public Utilities spokesman Jeremy Woodrow said.
Woodrow said 30 miles (50 km) of the Richardson Highway remain closed for the foreseeable future, in part because a lake had formed below the avalanche that must now recede. Some sections of the highway also remain unstable and unsafe.
Crews were working on the northern end of the avalanche area, Woodrow said, but even when the waters recede, clearing the highway would not be a routine snow-plowing job.
"We will be restricted because there is only so much equipment you can get up there at one time," he said. "There is limited space for everything, but once water recedes, we'll be working on both ends, north and south."
Valdez, one of Alaska's main seaports, lies in a remote area of the Chugach Mountains. City officials said on the Valdez website that volunteer evacuation precautions are being made.
RESIDENTS URGED TO LEAVE
Officials have set up shelters and urged some residents to leave their homes as a precaution, according to the website. Authorities also planned to conduct aerial surveillance and hold an emergency City Council meeting Monday evening.
"There is plenty of gasoline and heating fuel oil in town to serve local needs during an extended road closure," said a statement posted late Sunday. "Should fuel run short at any time, it will be barged in as needed."
The town's 4,000 residents depend on barges for most delivered goods, rather than the highway.
The city reported on its website Monday morning that a shipment for a local grocery had arrived by barge. Still, the state's ferry system has added two ferry sailings and ERA Alaska has added a late afternoon flight.
Schools in the town remain open, as do airport and port facilities, officials said.
Valdez is also the terminus port for more than 550,000 barrels of North Slope crude oil flowing daily through an 800-mile (1,287-km) pipeline starting in Prudhoe Bay.
Michelle Egan, a spokeswoman for pipeline operator Alyeska Co, said the avalanches have not disrupted throughput because the pipeline is buried beneath the avalanche area. They have also had no effect on the tanker loading terminal or deliveries, she said.
"The original TAPS (trans-Alaska pipeline system) design engineers took the terrain and conditions into account," Egan said.
"There are valves in the area that we are monitoring, but they are not compromised by avalanche or flooding. We are flying into the area regularly for surveillance and accessing surveillance info from the City of Valdez as well," she said.
Valdez was recently named by Weather.com as the snowiest city in the nation, with an average annual snowfall of 326 inches (8.28 meters). (Additional reporting by Karen Brooks; Writing by Dan Whitcomb; Editing by Eric Walsh)