Low visibility in the sky due to exploding volcano 1 km away. Lightning strikes can be seen in the large ash cloud. More context: "I drove up to a volcanic eruption in Grimsvotn, at Vatnajökull glacier, Iceland... the biggest glacier in Europe. Plume of ash shoots 20 km in the air between 4 and 6 am May 22nd, 2011, causing air traffic jams. Location: 1 km from eruption. We were the first ones there, before the government could reach it and block access. We drove up across the glacier on specially modified trucks for Icelandic highlands. What looks like clouds, is a snow storm we got ourselves in. At this time we were getting heavy ash fall and flying lava rocks were hitting us frequently."