Hawaiian Volcano Observatory: Episode 39 lava fountaining from the south vent stopped at approximately 2:13 a.m. HST on December 24 after 5.9 hours of sustained fountaining. The two vents within the north cone both stopped slightly earlier at 2:00 a.m. HST. Sustained fountaining began at 8:20 p.m. HST from the north and south vents after just under 2 hours of precursory overflows. Fountains rapidly grew to several hundred feet high and by 9:30 p.m. HST had reach maximum estimated heights of 1,400 feet (425 meters) for the south fountain and 900 feet for the north fountain. The main fountain from the north cone came from the “right hand” vent (as viewed from V1cam, which is pointed south), but a much smaller fountain, 100-200 feet (30–60 meters) high, began at about 8:45 p.m. HST and lasted until the north vent stopped fountaining. This “triple” fountain lasted through most of the eruption, with the south fountain highest followed by the “right hand” north vent (about 65–70% of the south fountain height) and the much smaller “left hand” north vent (about 10–20% of the south fountain height). The highest peak or instantaneous effusion rate of 960 cubic yards per second (800 cubic meters per second) occurred about 9:00 p.m. HST just before the south and north vents reached their maximum heights. Episode 39 ended with an average effusion rate of 250 cubic yards per second (190 cubic meters per second). An estimated 12 million cubic yards (9.3 million cubic meters) of lava erupted and covered about 50–60% of the floor of Halemaʻumaʻu crater. The Uēkahuna tiltmeter (UWD) recorded about 26.8 microradians of deflationary tilt during episode 39.