From snow to smoke in four days; from boom to bust in a stockbroker’s heartbeat. You could not find better images for the unpredictability of Alberta and Calgary.

A $7 billion deficit – or more — wouldn’t be surprising. But it would devastate public confidence.

Politics at least may seem stable — we’ve got a majority NDP government, you know — but on the ground it’s a bubbling cauldron, both in the Calgary-Foothills byelection and the federal campaign.

Here’s the key fact: Since West Texas Intermediate (WTI) oil traded at an average of US$93 a barrel in 2014, the Alberta treasury is on course to lose $7.8 billion in revenue, should oil linger in the $40-per-barrel range for a full year.

Every one-dollar drop costs the government $148 million. A 10 per cent slide in natural gas costs $31 million. This is somewhat mitigated by the weak dollar, which brings in $61-million extra for each penny of value lost in the loonie.

The full revenue losses over calendar 2015, or budget year 2015-16, can’t be known yet. But it’s clear we will be short many billions of dollars from revenue levels seen when oil sold above $90 for four straight years, beginning in 2011.

And yet, despite the revenue bonanza, the Progressive Conservative government still ran deficits for three of those four years (or all four, if you prefer Wildrose accounting.)

Jim Prentice’s March budget, which got him defeated before it was passed, forecast $55-a-barrel oil for the fiscal year 2015-2016.

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Even with that forecast, Prentice expected a $5-billion deficit.

Now, crude oil is running $15-per-barrel lower than his estimate. That’s a further $2.2-billion revenue loss. And some experts forecast a price skid below $40.

So, what will the deficit be when the New Democrats finally produce a budget, likely in late October, with the byelection and federal election safely over?

It’s hard to imagine a figure below $6 billion, given NDP spending promises and the reversal of some Prentice cuts, especially to health-care growth.

Notley’s candidate was jeered at a candidates’ forum when he said the NDP is a friend of the oil industry.

An even bigger deficit — $7 billion or more — wouldn’t be surprising. But it would devastate public confidence.

The angst in NDP circles is palpable. To maintain some sense of momentum, they’re throwing everything at the Calgary-Foothills byelection, to be held Sept. 3.

Counting her Tuesday night appearance in Calgary, Notley has been in the riding three times, speaking and campaigning with NDP candidate Bob Hawkesworth.

It’s unusual for a premier to risk personal political capital on a byelection held so soon after a general election, with a safe majority in hand. But this one is vital to government momentum and credibility in Calgary.

The omens aren’t so good.

Hawkesworth trails Wildrose candidate Prasad Panda in one survey, even though the conservative vote is again sharply split, with the PCs polling a surprising 20 per cent. Hawkesworth was jeered at a candidates’ forum when he said the NDP is a friend of the oil industry.

You have to feel for Notley. Four months ago she didn’t expect to be premier. Now she’s walked into the biggest mess to confront a new premier since the PCs took office.

Oil prices fell months after Don Getty took office in 1985. They fell two years after Ed Stelmach became premier in 2006.

Even Prentice had a bit of time to get his feet on the ground after taking over last Sept 15.

Oil was still above $90 a barrel the day he was sworn in. It quickly began to slide, and by November he was hinting at tax hikes to deal with the crisis of the day — $74 oil.

There’s a credible argument that low oil prices destroyed, or contributed to the eventual destruction, of all three careers.

Notley has it much worse. She landed with an inexperienced crew in the middle of a severe and escalating crisis.

And one damaging result, as the NDP try frantically to get a grip on government, is the failure to offer any concrete plan for grappling with this horrendous problem.

On Tuesday Notley said any responsible government looks at spending restraint in such times. She promised to protect core services. She wouldn’t say if Finance Minister Joe Ceci’s deficit estimate – $5.4 billion – is still in the ballpark.

Those are platitudes, not plans. Albertans need to know a lot more, long before the budget that won’t come until late October at the earliest.

Don Braid’s column appears regularly in the Calgary Herald

dbraid@calgaryherald.com