* Several Everest climbing teams decide to pack up
* Accident last week has shocked mountaineering community
* Angry Sherpas demand greater protection
* Nepal to extend climbing permit for those who leave
By Gopal Sharma
KATHMANDU, April 24 (Reuters) - Several foreign climbing expeditions have called off attempts to scale Everest following an avalanche that killed at least 13 local guides, meaning Nepal faces an entire season without a single ascent of the mountain for the first time in decades.
The toll from last Friday's accident was the highest in a single day in Everest history, and many Sherpas who are angry over their treatment at the hands of foreign mountaineers and the government have refused to guide visitors up the climb.
Three Sherpas are still missing since an avalanche struck while they were fixing ropes and cracking snow and ice to carve out a route for foreign climbers through the Icefall, near the base camp for most climbs on the Nepali side of the mountain.
The U.S.-based International Mountain Guides (IMG) became the largest team to pull out in response to the tragedy. It had around 40 climbers in three teams on the mountain.
"The Icefall route is currently unsafe for climbing without repairs by the Icefall doctors, who will not be able to resume their work this season," the group said on its website.
"We have explored every option and can find no way to safely continue the expedition."
The Peak Freaks Everest 2014 expedition also pulled out for safety reasons, and said that the Nepalese government had officially closed Everest for the season.
But Sushil Ghimire, a senior bureaucrat at the tourism ministry, said some teams may yet decide to attempt to scale the summit. Foreign expeditions on the Tibetan side of the mountain remained unaffected.
Ghimire told Reuters that the government would extend the climbing permit for five years to climbers who withdrew after the accident, meaning they can return without paying twice.
"This is a special concession from the government," he told Reuters, after returning from a meeting with the Sherpa guides at the base camp.
"Some teams may withdraw while some may climb. It has been agreed that no one will stop those mountaineers who want to climb Everest in the current season itself."
Vern Tejas of the Seattle-based Alpine Ascents, which lost five of its guides in the accident, said the group was coming back out of respect to the guides who lost their lives.
Also returning was New Zealand's Adventure Consultants team that lost three guides.
The mountaineering season lasts until the end of May, when cloud from the rainy season pushes up from the south making climbing the world's highest mountain virtually impossible.
With such a small window of opportunity for the climbers to reach the top, mountaineering experts believe Nepal's Everest season is effectively over before a single successful ascent has been completed.
Earlier this week, the government said it would raise the minimum insurance cover for Everest guides by 50 percent, set up a relief fund for the welfare of the victims' families and pay for the education of their children.
The accident has shocked the international mountaineering community and highlighted the risks that Nepalese guides run to help foreign climbers scale Everest.
It has also provoked criticism that the government takes hefty fees for climbing permits but does little for the guides themselves.
Guiding foreign climbers is the main livelihood for Sherpas, helping them make up to $7,000 - and some even more - each year in a country with an average annual income of just over $700. (Editing by Mike Collett-White)