A grave natural disaster like the cyclone that ripped through southern Burma is a moment of reckoning for an authoritarian regime. It cannot fight the disaster as it fights the Karen rebels on the border, destroying their villages and crops, killing their animals and driving them into exile. It cannot descend as it did on the thousands of monks who demonstrated in the nation's towns and cities last September, shooting and beating and arresting them.

The State Peace and Development Council (SPDC), as Burma's military junta styles itself, argues that military government is essential for Burma because of the threat to the nation's unity from secessionist groups on the borders. Democracy cannot be permitted because Burma is in a permanent state of emergency.

But a real, full-scale natural emergency like this one is a challenge of a different kind. At the start of the emergency the junta behaved according to form: it did nothing. It gave no warnings: the columns of the torpid official newspapers were still full of exhortations to people to vote yes in a referendum on a new pseudo-democratic constitution, which is scheduled for 10 May.

It is no surprise if the SPDC does little or nothing to bring relief, because since losing the general election of 1990 to Aung San Suu Kyi's National League for Democracy it has behaved as if the people – or the 82 per cent who voted NLD – were the Enemy Within. They exist to be exploited, bullied, silenced, forced to work for nothing, and shifted from land the army wants. The bizarre decision to move the capital to the remote new town of Naypyidaw, hundreds of miles from Rangoon, the former capital, was the latest sign that the regime wants as little to do with the people it rules as possible. They dominate the people through elaborate networks of informers and vigilantes. Soldiers or police appear only when there is serious trouble.

But yesterday came the turning point: as the number of casualties officially admitted jumped tenfold from 400 to 4,000, and then immediately to 10,000, the regime seems to have realised that denial was no longer an option. Yesterday the Foreign minister, Nyan Win, said Burma would welcome international aid.

The junta does not want foreign aid workers swarming through the land. The regime has vowed to press on with the referendum, and the last thing it wants is foreigners poking their noses into the process.

But if they continue to do nothing, some kind of popular revolt is probable. "This country is a volcano," a dissident intellectual told me in Mandalay in March. "It could erupt at any time." And it is always at moments of dramatic crisis that the Burmese people's patience snaps. Better, perhaps, the generals may have decided, to bring in foreign aid quickly to avoid an outbreak of violent disorder.

The change of mind could have dramatic consequences. After 2004's tsunami, the Indonesian government welcomed foreign aid – and the Indonesian army looked on aghast as the military of Australia and the United States flew incessant missions in and out of the stricken city. The unexpected upshot: the end of the guerrilla war between the Free Aceh Movement and the government, and a peace agreement which still holds.

But Burma is unlikely to be so lucky. Too much has been too wrong, for too long. But foreign aid would be like a long cold drink of water to a man dying of thirst. Quite aside from the immediate relief it would bring.