Early during episode 22 of the ongoing summit eruption at Kīlauea volcano, lava fountains reached more than 500 feet (150 meters) above the north vent within Halemaʻumaʻu crater. This image was captured from the northwest rim of the crater around 8:40 a.m. on Friday, May 16. USGS photo by M. Zoeller.

Late during episode 22 of the ongoing summit eruption at Kīlauea volcano, lava fountains failed to even reach 160 feet (50 meters) above the north vent within Halemaʻumaʻu crater. This image was captured from the northwest rim of the crater around 2:00 p.m. on Friday, May 16. USGS photo by M. Zoeller.

Downwind of lava fountains from the ongoing Kīlauea summit eruption, substantial tephra is being deposited on the rim of Halemaʻumaʻu crater. In this photo captured on Friday, May 16 from the northwest rim of the crater looking to the southwest, tephra clasts up to a yard (meter) across can be seen raining down and kicking up dust as they break upon impact with the ground. USGS photo by M. Zoeller.

During the ongoing Kīlauea summit eruption, not all spatter in the lava fountain falls as solid tephra outside Halemaʻumaʻu crater; instead, some remains molten and feeds lava flows on the flanks of the eruptive vents. In this image captured on Friday, May 16, two spatter-fed flows can be seen descending the north side of the north vent. The one to the upper left is a smoother pāhoehoe flow and the one to the lower right is a rougher ʻaʻā flow, both of which would be more viscous than most of the lava that has been gushing out of the vents during this eruption. USGS photo by M. Zoeller.