Electrical lead time during an extreme haboob-like dust-front intrusion in Ica, Peru

Extreme dust storms evolving on sub-hourly timescales challenge conventional air-quality monitoring systems, as particulate matter (PM) sensors require sufficient aerosol accumulation before threshold exceedance is detected. The extent to which atmospheric potential gradient (PG) measurements can provide earlier indicators during rapidly evolving frontal dust intrusions remains insufficiently quantified.We evaluate PG detection latency during an unusually intense haboob-like dust outbreak that impacted Ica, Peru (14.07°S, 75.73°W), on 31 July 2025. Two ground-based stations separated by 13.6 km recorded PG and PM₂.₅ at minute-scale resolution. Frontal arrival times were independently constrained using GOES-19 ABI RGB imagery (10-min cadence) and 1-min ground-based cameras. Electrical detection was defined using objective seasonal baseline-departure criteria with multi-threshold persistence constraints.PG exhibited an initial statistically significant deviation (2σ) at 12:25 LT, more than 100 min prior to local particulate enhancement. A conservative rapid-growth onset (5σ) occurred at 13:48 LT, preceding both the PM₂.₅ increase at the urban station by 24 min and the camera-defined frontal impact by approximately 23 min. The event displayed a pronounced bipolar electrical structure, with PG amplification immediately before particulate onset followed by a sub-minute polarity reversal during frontal passage.These results indicate that high-resolution PG monitoring captures organized boundary-layer electrification associated with density-current dust fronts and may provide earlier detection than mass-based aerosol sensors in this extreme case. However, operational skill, false-alarm rates, and generality require evaluation using longer multi-event records.