Photo: The Canadian Press. All rights reserved.

The NDP has won a majority in Alberta by toppling the Progressive Conservative colossus that has dominated the province for more than four decades.

The party under leader Rachel Notley swept all 19 seats in Edmonton on Tuesday and made inroads in previously barren NDP territory in Calgary and Lethbridge.

The Wildrose party appeared poised to take second place and form the official Opposition, while Premier Jim Prentice and his PCs were trailing in third.

It's a tectonic shift in Alberta politics, which has seen government change hands only four times since the Liberals won the first election when Alberta became a province in 1905.

The Tories, first elected in 1971, had been the longest-serving government in Canadian history at 43 years and almost eight months.

For Notley, the victory is a vindication of the pioneering efforts of her father, Grant Notley. He helped found Alberta's NDP and kept the movement alive as the sole NDP member of the legislature in the 1970s.

He died in a plane crash in northern Alberta in 1984, two years before his party made its first big breakthrough in 1986 and became official Opposition.

The NDP has never come close to power in Alberta since it began contesting votes in 1940. Its previous high-water mark was 16 seats and almost 30 per cent of the popular vote in 1986.

Notley ran on a policy platform of social change, promising to invest more in schools and hospitals, while increasing taxes to corporations and the wealthy.

His party had been seeking to stave off challenges from both the NDP and the Wildrose party to secure a 13th consecutive majority government.

Prentice dropped the writ on April 7 — a year earlier than necessary under Alberta law — saying he needed a mandate to implement a tough budget that proposes sweeping increases in taxes and user fees and cuts in government spending.

The goal was to stop Alberta's heavy reliance on fluctuating oil prices for its revenue.

It was supposed to be a victory lap for the premier, whose party held 70 of 87 seats at dissolution. The Wildrose and the Liberals were both coming off leadership changes.

The campaign didn't work out that way.

The Opposition Wildrose criticized Prentice for not going far enough with spending cuts and said it would not raise any taxes.

Leader Brian Jean promised to balance the budget by 2017 through cuts to scores of management jobs, reprioritizing building projects and holding the line on taxes.

The New Democrats criticized Prentice for going too far with cuts, while sparing corporations from tax increases. Notley said she could balance the books by 2018 through increased taxes on corporations and the wealthy, while still spending more on health and education.

Notley has had momentum since the leaders debate that most pundits say she won.

The Liberals, under interim leader David Swann, ran a low-key campaign that promised to fix long wait times for health care and improve social services for young and old.