Global warming activists stormed Washington Monday for what was billed as the nation's largest act of civil disobedience to fight climate change -- only to see the nation's capital virtually shut down by a major winter storm.

Schools and businesses were shuttered, lawmakers cancelled numerous appearances and the city came to a virtual standstill as Washington was blasted with its heaviest snowfall of the winter. 

It spelled about six inches of trouble for global warming activists who had hoped to swarm the Capitol by the thousands in an effort to force the government to close the Capitol Power Plant, which heats and cools a number of government buildings, including the Supreme Court and the Capitol.

The snowy scene, with temperatures in the mid-20s, was reminiscent of a day in January 2004, when Al Gore made a major address on global warming in New York -- on one of the coldest days in the city's history.

Protest organizers said about 2,500 people braved the blizzard to oppose greenhouse gas emissions, but the shroud of snow wasn't the only wet blanket in the nation's capital Monday.

House Speaker Nancy Pelosi, who called on the architect of the Capitol to stop burning coal at the power plant last week, cancelled her appearance at the rally because her flight to Washington was cancelled.

Michelle Obama canned a public "Read Across America" event and HUD Secretary Shaun Donovan canceled a meeting with the Democratic Caucus because the members of Congress couldn't get to D.C. An honor cordon at the Pentagon for Afghanistan's defense minister also had to be called off.

Some protesters couldn't make it as dozens of flights in the area were delayed or called off, and some couldn't face the dangerous roads or blustery weather, leaving hundreds safe, if sorry, back at home. 

One protester named Kat had planned to get arrested and be bailed out Monday but decided to stay put and donate her money to a good cause instead.

"I don't want to travel in the snow today. However, I am donating my bail money to fight mountaintop removal," she wrote to the Climate Action Web site.

Even marchers in gloves and parkas were wringing their hands to stay warm, and some protest leaders were having trouble providing updates on blog sites like Twitter.

"I admit, it's hard to tweet with cold hands!" wrote the author of the Capitol Climate Action Web site, who said the activists were "staying warm with a chant: 'Clean coal is a dirty lie.'"

The plant has been seized as a symbol of the government's energy excess, and the 99-year-old facility accounts for a third of the legislative branch's greenhouse gas emissions.

Protesters gathered earlier Monday in the Spirit of Justice Park near the Capitol and marched a few blocks to the power plant, where D.C. police set up a careful cordon.

In a press release supporting the protest, Greenpeace wrote that "coal is the country's biggest source of global warming pollution" and that "burning coal cuts short at least 24,000 lives in the U.S. annually."

On a blustery, frigid day, it might be worth noting the government's own stark numbers: pneumonia kills twice as many each year.