In April 2022 a seismic swarm near Mt. Edgecumbe in southeast Alaska suggests renewed activity at this dormant volcano located in a transform fault setting. Oral Tlingit history describes low-level basaltic eruptions $\approx$800 years ago. Thin rhyolitic tephras deposited 5-4 ka. We analyze synthetic aperture radar data from 2014-2022 and resolve rapid inflation up to 8.7\,cm/yr beginning in August 2018. Bayesian modeling suggests a gently westward dipping sill opened 0.65\,m between 7.6\,km to 5.3\,km depth, centered about 2-3\,km east of Mt. Edgecumbe. Reanalyzed seismicity, recorded 25\,km away, shows increased activity since July 2019. We hypothesize mafic magma ascent through ductile material, accumulating below a silicic seal or in a silicic reservoir, and triggering seismicity in the overburden. Cloud-native open data and workflows enabled discovery and analysis of this rapid inflation within days after going unnoticed for $>$3 years.