In a special bulletin from 0600 on 3 June INSIVUMEH noted increased activity at Fuego. Strong explosions were accompanied by rumbling sounds, and shock waves that vibrated local structures. Dense ash plumes rose 2.3 km above the crater and drifted SW, W, NW, and N. Pyroclastic flows descended the Seca (Santa Teresa) drainage on the W flank, and possibly other drainages, though poor weather conditions prevented clear views of the summit area. Ash plumes drifted in westerly directions, causing ashfall (on roofs and cars) in Sangre de Cristo (8 km WSW) and San Pedro Yepocapa (8 km NW). By 1000 pyroclastic flows were descending the Cenizas (SSW) drainage. Ashfall was reported in additional areas including La Soledad (10 km ESE), Quisache, and the municipality of Acatenango (8 km E).

Based on information from multiple agencies, the Washington VAAC reported an ash plume rising to 9 km (30,000 ft) a.s.l. at 1130 from an explosive eruption. In a report from 1340, INSIVUMEH described large pyroclastic flows traveling down the Seca, Cenizas, Mineral, Taniluya (SW), Las Lajas (SE), and Honda (E) drainages, producing dense ash plumes that rose 6.2 km above the summit (or 32,800 ft a.s.l.). A news article stated that the pyroclastic flows traveled at least 8 km and reached temperatures of 700 degrees Celsius. Tephra and lapilli fell in areas more than 25 km away, including in La Soledad, San Miguel Dueñas (10 km NE), Alotenango, Antigua Guatemala (18 km NE), and Chimaltenango (21 km NNE). Ashfall was reported as far away as Guatemala City, 70 km E. Explosions rattled structures within 20 km of Fuego. The La Aurora International Airport closed at 1415. Eyewitness accounts described the fast-moving pyroclastic flows inundating fields people were working in, overtaking bridges, and burying homes up to their roof lines in some areas. San Miguel Los Lotes, Alotenango, and El Rodeo (10 km SSE) were the worst affected.

According to Simon Carn, satellite data analysis showed that the event produced the highest SO2 loading measured from a Fuego eruption in the satellite era (since 1978), and therefore most likely the highest since the major 1974 eruption. He went on to note that the SO2 mass was about ~2 orders of magnitude than the 1974 eruption, which had a significant stratospheric impact.

At 1650 INSIVUMEH noted reports of lahars descending the Pantaleón drainage (fed by the Santa Teresa and El Mineral rivers) and other drainages. CONRED had evacuated communities near Fuego, including Sangre de Cristo, finca Palo Verde, and Panimache. At 2200 (~16.5 hours after the increased activity began), the eruption waned, with activity characterized by weak-to-moderate explosions, crater incandescence, and ash plumes that rose almost 800 m. The seismic station (FG3) recorded the last pyroclastic flow at 1845. By 0725 on 4 June seismicity had returned to normal levels. Explosions occurring at a rate of 5-7 per hour produced ash-rich plumes that rose as high as 900 m and drifted 15 km SW, W, NW, and N. Avalanches of material descended the flanks. The La Aurora International Airport reopened and flights resumed at 0930.

On 5 June INSIVUMEH reported that activity again increased. Explosions occurring at a rate of 8-10/hour, some strong, generated ash plumes that rose 5 km and drifted E and NE. At 1928 a pyroclastic flow traveled down the Las Lajas drainage. News articles noted that authorities called for another evacuation.

CONRED reported that by 0630 on 6 June a total of 12,089 people had been evacuated, with 3,319 people dispersed in 13 shelters. One bridge and two power networks had been destroyed. According to news sources on 6 June, Guatemala's National Institute of Forensic Sciences stated that 75 people were confirmed to have died and 192 were still missing. Many, possibly thousands, received burns and other injuries. Weather conditions, continuing activity at Fuego, poor air quality, hot pyroclastic flow deposits, and rain made rescue efforts difficult.

Sources: Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia (INSIVUMEH), Coordinadora Nacional para la Reducción de Desastres (CONRED), Washington Volcanic Ash Advisory Center (VAAC), Simon Carn, NASA Earth Observatory, BBC News, The Guardian News, ABC News - American Broadcasting Corporation, U.S. Embassy in Guatemala

Based on satellite data, the Darwin VAAC reported that on 5 June a minor ash emission from Kerinci rose to an altitude of 4.3 km (14,000 ft) a.s.l. and drifted W.

Source: Darwin Volcanic Ash Advisory Centre (VAAC)

HVO reported that the eruption at Kilauea’s Lower East Rift Zone (LERZ) and at Overlook Crater within Halema`uma`u Crater continued during 30 May-6 June. Lava fountaining and spatter was concentrated at Fissure 8, feeding lava flows that spread through Leilani Estates and Lanipuna Gardens subdivisions, and reached the ocean at Kapoho Bay. Fissures 22, 6, and 13 were periodically active on 30 May, and fissures 6/13 spattered on 4 June. Sluggish lava flows were present around Fissure 18.

Inward slumping of the crater rim and walls of Halema`uma`u continued, and earthquake activity beneath the caldera was mostly high, as the summit area adjusted to the withdrawal of magma from Overlook Crater. Passive degassing of SO2 from the summit decreased, but emission rates were high enough to impact air quality downwind. Ash emissions were intermittent and low, though around 1100 on 30 May an ash plume rose to 3.6 km (12,000 ft) a.s.l. A small explosion was detected at 1339 on 1 June. A preliminary M 5.5 earthquake was recorded at 1550 on 3 June, producing an ash plume that rose to 2.4 km (8,000 ft) a.s.l. A small explosion and accompanying M 5.5 earthquake was detected at 0432 on 5 June; an ash plume rose to 1.6 km (5,100 ft) a.s.l.

During the beginning of the reporting period Fissure 8 generated tall lava fountains, rising 80 m, and some secondary fountains that rose 18 m. Pele's hair and other volcanic glass from the high fountaining fell in areas W of the fissure and within Leilani Estates. A small (30 m high) spatter cone formed at the downwind side of the fountain. Volcanic gas emissions from the fissures were very high; trade winds blew vog to the S and W parts of the island.

The lava flow fed by Fissure 8 advanced NE at a rate of 550 m/hour during 29-30 May, but then slowed to 90 m/hour on 31 May. High eruption rates led to the formation of a leveed channel along the W edge of the lava flow; small overflows from the channel occurred along its length. On 2 June lava flowed around the N part of Kapoho Crater and then turned S, entering the Vacationland neighborhood. At 0700 the flow front had entered Kapoho Beach Lots, moving about 75 m/hour. Lava entered Green Lake (70 m x 120 m in dimension, and 60 m deep) at 1000, creating a large steam plume. By 1500 lava had completely filled the lake and boiled off the water. Locals reported that lava (with a flow front 800 m wide) entered the ocean at Kapoho Bay around 2230. By late afternoon on 4 June lava had built a delta extending almost 700 m into the bay.

Overnight during 4-5 June lava fountaining at Fissure 8 was less vigorous, with a maximum height of 55 m. By 0630 on 5 June lava had completely filled Kapoho Bay, creating a new coastline 1.1 km away from the former coastline. To the S lava had overtaken most of the Vacationland subdivision and was entering the tidepools. All but the northern part of Kapoho Beach Lots had been covered.

Source: US Geological Survey Hawaiian Volcano Observatory (HVO)

PVMBG reported that at 0820 on 1 June an event at Merapi generated an ash plume that rose at least 6 km above the crater rim and drifted NW, but then winds changed to the SW. Ashfall was reported at the Selo observation post. Observers noted white smoke rising from a forested area 1.5 km NW, possibly indicating burning vegetation. The report noted that volcano-tectonic events were occurring at about 3 km below the crater. Later that day at 2024 an ash plume from a 1.5-minute-long event rose 2.5 km above the crater rim and drifted NE and W. At 2100 an ash plume rose 1 km and drifted NW. The Alert Level remained at 2 (on a scale of 1-4), and PVMBG noted that all people within 3 km of the summit should be evacuated.

Source: Pusat Vulkanologi dan Mitigasi Bencana Geologi (PVMBG, also known as CVGHM)