In recent years, natural disasters around the world have been chronicled by a new kind of visual journalism, often produced by citizen eyewitnesses and posted to the video sharing site YouTube. These videos represent a way of “crowdsourcing” a dramatic breaking news event, frequently before professional journalists can arrive on the scene.

In the first 24 hours after the deadly tornado slammed into Moore, Okla. around 3 p.m. on May 20, these citizen journalists produced a majority of the most viewed YouTube videos that went viral after the tragedy.

According to a Pew Research search of videos connected to the disaster, in the 24 hours immediately after the tornado struck, the 10 most viewed YouTube videos of the event were seen a combined 1.8 million times. Seven of those 10 videos, ranging in length from 28 to 194 seconds, were shot by eyewitnesses unaffiliated with a news organization.