Updated

Clouds 1, Russian air force 0.

That was the score at this year's Victory Day parade over Red Square, where thick clouds blocked most warplanes and helicopters from the flyover that traditionally concludes the observance of the anniversary of Nazi Germany's surrender.

For years, authorities have tried to ensure clear skies for the Moscow parade by conducting cloud-seeding.

The state news agency Sputnik says the technique involves specially equipped planes spraying dry ice and other reagents on clouds away from the area where clear skies are desired. The dry ice crystallizes the moisture and the clouds either disperse or dump their moisture away from the festivities, Sputnik says.

On Monday, the Defense Ministry said the cloud-seeding planes would be deployed for this year's parade, but there was snow in Moscow Monday and it was unclear if they were sent into action.