Overview
- After several quiet years, Echinus first erupted on February 7, followed by additional eruptions on February 9, 12 and 15.
- Beginning February 16, eruptions repeated every 2 to 5 hours, lasting 2 to 3 minutes and reaching about 20–30 feet, echoing a 2017 pattern.
- Recent monitoring shows activity tapering to temperature spikes and surges with few or no full eruptions, with some reports noting none after February 24.
- Echinus is the world’s largest acidic geyser, with mildly acidic water (about pH 3.3–3.6) that produces vivid red, orange and yellow rims from iron, aluminum and arsenic.
- USGS and the park publish real-time temperature graphs and caution that water exceeds 200°F, urging visitors to stay on boardwalks; the current phase’s duration is uncertain and viewed as unlikely to persist into summer.