The first road stage of the Tour de Romandie has been shortened to just 88km after heavy snow on the Simplon Pass forced the race organisers to avoid the 2000m high climb.
The revised stage will start in Brigerbad at 3:15pm local time and end as scheduled in Sion at 5:00pm.
The riders are due to travel from Ascona to Sion by train, with other race vehicles traveling via the Gothard or St. Bernard passes.
The Polish national champion went off early and set a time of 6:22 for the hilly course. Australia's Rohan Dennis (Garmin-Sharp) showed his stage race credentials by finishing second, four seconds slower than Kwiatkowski. Sprinter Marcel Kittel (Giant-Shimano) was third, also at four seconds. World champion Tony Martin (Omega Pharma-QuickStep) finished fifth at five seconds.
Chris Froome (Team Sky) was the last rider to start as the 2013 winner and finished 13th, nine seconds slower than Kwiatkowski. Tejay van Garderen (BMC) crashed during his ride and lost close to three minutes.
Kwiatkowski will wear the race leader's yellow jersey during the shortened stage but played down his chances of overall victory.
"It's hard to say if I can win overall. I'll look at the GC day by day," said Kwiatkowski. "It depends on how I recover from the Ardennes Classics. This is the last race of my spring season. We've got good riders with Tony Martin and Rigoberto Uran, so we're looking forward to the next few stages."