Eurosport - Mon, 10 May 17:31:00 2010
Both road stages in the Netherlands have been littered with crashes and Britain's first stage winner Bradley Wiggins was involved for the second successive day in one of the bigger pile-ups on the 224km trek from Amsterdam to Middelburg.
Australian world champion Evans did not hit the deck in that incident in the latter stages but he was delayed by the chaos and lost contact with the front group, eventually finishing 46 seconds behind.
"With 10km to go, I had done everything right, I put myself everywhere (to be safe) and was relaxed and there was no wind," Evans said.
"Then, I came around a corner and the whole Sky team was on the ground. (Suddenly), guys were falling on top of me. Losing 40-some seconds to my competitors isn't something I wanted to give up."
Quick Step's Weylandt took the stage after Columbia-HTC sprinter Andre Greipel, the winner of most races in 2010, was caught out on the final bend.
The 25-year-old from Ghent, who also won a stage at the 2008 Vuelta a Espana, held off Rabobank's Australian sprinter Graeme Brown with Robert Forster in third place ahead of Danilo Hondo and young Brit Adam Blythe.
Vinokourov, the 36-year-old Kazakh whose two-year ban for blood doping ended last July, now leads young Tasmanian Richie Porte on GC after both finished in the lead group of 26 riders. They are on the same time with Scotland's David Millar just one second behind.
Belgium's Olivier Kaisen (Omega Pharma-Lotto), Frenchman Jerome Pineau (Quick Step) and Dutchman Tom Stamsnijder (Rabobank) established the break of the day and built up a lead of eight minutes but strong crosswinds caused splits in the peloton and the subsequent increase in speed from the main pack saw them caught 90km from the finish.
A frenetic final hour saw several groups split while American Christian Vande Velde from Garmin was forced to abandon after a crash before the pile-up at a tight corner saw four Sky riders on the floor including Wiggins who finished nearly four minutes behind the stage winner.
The decision to hold the first three stages of this year's Giro in the bike-mad Netherlands looked to have been a good one after a captivating opening time trial in Amsterdam on Saturday but organisers will now be scratching their heads.
The peloton will fly to Italy as planned to continue the three-week race on home soil on Wednesday.
Luxury buses had been put on stand-by to drive the Giro back to Italy due to the threat of flight cancellations because of the volcanic ash.
Giro - Stage 4: Wednesday 1.30pm LIVE on British Eurosport 2 (Sky 411 / Virgin 525) & on the Eurosport Player.