Yamaha R1 Crashes Because of Cold Tires [Video]
Such a crash is indeed silly because it can actually happen to pretty much anyone, and older, experienced riders just know luck can run out at any time. It's silly because one needs no sudden maneuvers or hard acceleration or brutal braking to come off the bike... it just happens.
With the cold weather settled in for weeks already the earth is severely chilled and so is the asphalt. When riding for 10 minutes cross-town or so, tires will not heat up, and even if you would leave home after heating them in wraps, they'll soon be just as cold.
Now, the math is really simple: cold rubber rolling on cold asphalt equals zero grip. And by all means, we've seen losing the front wheel traction during a casual low-speed corner before. Ride carefully, or just think whether it's not better to just leave the bike at home this time. And the next time... until spring.