The treacherous moment when rookie cyclists, eager to participate in the Portland bike scene they’ve heard about, hit the roads (and meander into traffic) at the first sign of nice weather. 

In a sentence:  “I’m glad you’re taking your new Bianchi out for a spin, Steve, but—holy bike box!—beware the Rides of March.” 

Related:  Dismember December (on Mount Hood’s ski slopes); the High-Risk Riviera (all area rivers on hot August days).