Lewis Hamilton set the fastest time in the second practice session for the Canadian Grand Prix before a rainstorm hit that saw him clatter into the barriers on a brave - arguably foolish - reconnaissance lap as the conditions worsened.
The track was dry for the first 40 minutes of the session and the teams made the most of the conditions by sending their drivers out on both the soft and super-soft compounds. The rain first hit at the hairpin and quickly made conditions too treacherous for slicks, sending the cars back to the pits and the fans searching for their rain coats.
With better weather forecast for the rest of the weekend, there seemed to be little to gain from heading out again, but that did not stop both Mercedes venturing out just as the rain intensified. To the delight of the drenched fans the cars picked their way around the track on intermediate tyres, with Hamilton leading the way but by the time he reached the hairpin the track surface was flooded with water. His Mercedes aquaplaned straight past the braking zone and into the run-off before meeting the deep tyre barriers with a hefty thud. The collision broke the front wing of Hamilton's car and effectively called an end to the session as conditions only got worse.
Hamilton walked away from the accident unharmed and the damage to the car is likely to be a simple fix for the Mercedes mechanics before final practice on Saturday morning. It was not the first hit his Mercedes had taken, however, as he also mounted the inside kerb at the final chicane while attempting a quick lap in the dry.
The times suggest he may have competition from both his team-mate Rosberg and the Ferrari drivers, with Sebastian Vettel 0.316s off the lead Mercedes and Raikkonen 0.322s off. Rosberg was fourth ahead of a cluster of Mercedes-powered cars from Pastor Maldonado to Felipe Massa and the two Red Bulls in ninth and tenth.
Nico Hulkenberg was 11th fastest despite a puncture on the left rear of his set of super-softs. Initial investigations by Pirelli suggested it was a problem with the rim rather than the tyre that caused the loss in pressure.