Telework Week landed in Washington just in time for the “snowquester” and a second storm that may be even harder to predict — the one potentially brewing after two major companies announced they are ending telework.

Yahoo chief executive Marissa Mayer announced last month that, as of June, the company’s employees generally will be banned from working off-site, and the electronics store Best Buy said Tuesday it will be canceling its telework program. Best Buy employees will still be able to work off-site, a company spokesman said, but will have to seek management permission.

Those moves haven’t stopped proponents of telework — including those in the federal government — who say allowing employees the flexibility to work from home or at other sites can be productive and cost-effective.

More than 110,000 federal workers pledged to telework at least one day this week as part of Telework Week, which ends Friday.

“It’s a big win-win for federal employees and taxpayers with respect to the federal work force,” said Bill Dougan, president of the National Federation of Federal Employees. “Agencies can reduce their costs, and it saves employees the time and money of a commute.”

The Telework Enhancement Act of 2010 is the underpinning of an effort to increase teleworking among federal employees.

Advocates say telework improves work-life balance, reduces environmental degradation, saves money for employees and the companies or agencies that employ them, and increases productivity.

“Federal agencies want to be one of the best places to work,” said Cindy Auten, the general manager of Mobile Work Exchange, the company sponsoring Telework Week. “In light of what we’re dealing with in the federal government, we need to ensure federal agencies become attractive places to work.”

Few, however, seemed willing to discuss Yahoo’s and Best Buy’s decisions.

Auten said she didn’t know enough about Yahoo’s specific circumstances to comment. But she said that each telework situation should be evaluated on a case-by-case basis.

“It’s not a one-size-fits-all approach,” she said.

Danette Campbell has been at the forefront of telework in the federal government since 1997. The senior adviser for telework at the Patent and Trademark Office said government telework will continue to expand.

Of the PTO’s 11,600 employees, 7,400 telework from home one to five days a week, Campbell said. About 4,000 are full-time teleworkers.

This has allowed the PTO to avoid the need for an additional $22 million worth of office space, Campbell said. “Even though we’re bringing in new employees on a regular basis, we don’t have to secure any additional real estate for those employees.”

The General Services Administration will not be renewing leases for seven of its buildings because of telework, Dougan said. Over the next year, the employees who work in those buildings will be moved to the central office.

The number of employees moving is greater than the building space allows for, but the space will be adequate because of teleworking, Dougan said.

“Because employees are teleworking part of the workweek . . . they require less space because they don’t have to store as many work products,” he said. In many cases, employees won’t have desks but will work at tables, saving money on office costs, Dougan said.

Yahoo and Best Buy, both struggling financially, have said teleworking has made it difficult to build more cohesion in hard economic times.

They may find agreement among private and public mid-level managers, some of whom have been among the biggest resisters to telework.

Some have said that they can’t properly manage employees unless they’re in the same space, Auten said. The federal government has noted its own difficulties in winning over managers.

The federal telework law outlines training requirements for the management of teleworkers and requires each agency to establish a policy under which eligible employees can telework. Employees are not required to telework.

The Office of Personnel Management reported last year that in a partial survey of agencies, 168,558 of the 684,589 workers eligible to telework had done so in the month of September 2011. There are more than 2 million federal employees.

The GSA’s cloud-based system allows any employee to work from anywhere, at any time, said Casey Coleman, the GSA’s chief information officer.

“I’m virtually working wherever I am,” said Mafara Hobson, the GSA’s press secretary. “That can be a good or a bad thing. There’s really no end to the workday.”