51:24 On Feb. 6 of this year, two groups of skiers went into Salt Lake City’s Millcreek Canyon for a day of powdery ski runs in the backcountry. They were experienced skiers, knowledgeable about the dangers of avalanches but were still caught by the uncertain, shifting conditions of a snow-packed mountainside. Four young people lost their lives that day. In the wake of this tragedy, we look at the history of avalanches, the snow science behind the slides and, critically, the human factor. Snow careening down a mountain generally only matters to us insofar that it affects humans. We’ll talk with three avalanche experts about what an avalanche is and what it means to us this Friday at noon.