Update 3.20pm: Authorities in Zermatt have begun an "air bridge" by helicopter to take tourists down to the village of Taesch.
An official said about 100 people could be evacuated per hour, conditions permitting.
Earlier: Swiss authorities near the famed Matterhorn peak have closed ski slopes, hiking trails, cable cars, roads and train services into Zermatt amid a heightened risk of avalanches, stranding 13,000 tourists in the town.
Janine Imesch of the Zermatt tourism office said power has been restored in the town and no people were at risk because authorities blocked access to the nearby ski slopes and hiking trails a day earlier.
Ms Imesch added: "There is nothing to panic about, everything is fine."
The office’s website earlier indicated that arrivals and departures from the town were not possible.
Katrin from Ristorante Al Bosco has not lost her sense of humour 😀 #riffelalpresort2222m #magicmoments #swissdeluxehotels #sandozhotels #leadinghotelsoftheworld #extremeweatherconditions #meteoschweiz #snow pic.twitter.com/LJg17VI6KF— RiffelalpResort2222m (@RResort2222m) January 9, 2018
It noted a "power breakdown all over Zermatt" and called on people to "stay at home" so as not to disrupt snow-clearing crews.
More to follow.