24 Sep 2026
| 24 Sep 2026
Status: this preprint is open for discussion and under review for Natural Hazards and Earth System Sciences (NHESS).
Brief communication: NISAR pixel offsets measure but do not statistically resolve pre-failure motion at the 26 August 2026 Bhote Koshi ice–rock avalanche, Nepal
Abstract. We analyse five NASA–ISRO Synthetic Aperture Radar (NISAR) pixel-offset pairs spanning the 26 August 2026 Bhote Koshi ice–rock avalanche, Nepal. The last pre-event pair estimates 0.96 m median displacement over 24 days, with its mean vector 18° from the topographic fall line. No pre-event interval exceeds the 95th percentile of spatial comparison distributions for displacement or directional coherence. We report rankings rather than detections. The co-event field lacks directional organisation in both processing chains. Available interval averages do not establish precursory acceleration and cannot isolate motion during the final week before failure.
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