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NOTE: <\/b>The Disasters Team is currently revising the legend on this dataset. Visualization properties are not finalized. Please consult the metadata on this page for reference.

Date of Images<\/b><\/p>

Pre-event<\/span>: 2025-10-08, 2025-10-10<\/span><\/p>

Co and Post-event: <\/span>2025-10-12, 2025-10-13, 2025-10-15<\/span><\/p>

Summary:<\/span><\/p>

The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory (JPL) and the California Institute of Technology produced maps showing areas affected by flooding in western Alaska in October 2025 using the OPERA Dynamic Surface Water Extent from Sentinel-1 (DSWx-S1) product. The flooding was triggered by the remnants of Typhoon Halong, which brought hurricane-force winds and record-breaking storm surge to the Yukon-Kuskokwim Delta region. The event caused catastrophic damage across multiple Alaska Native coastal villages, including Kipnuk and Kwigillingok, where floodwaters swept homes from their foundations, destroyed infrastructure, and disrupted access to essential services.<\/span><\/p>

These maps provide an initial view of the surface water extent observed following the flood event. The results presented here are preliminary and unvalidated, intended primarily to support situational awareness and field response efforts. The ARIA-Share platform emphasizes rapid dissemination of satellite-based products for disaster response. All information is provisional and should be used under emergency response guidelines. These data are provided without warranty of any kind. Use at your own risk.<\/span><\/p>

OPERA DSWx-S1<\/span><\/p>

The OPERA DSWx-S1 was used to identify surface water for the flooding event. The images provided are a mosaic of OPERA DSWx-S1 products, producing a composite image for each date. The mosaicking applied prioritized pixels classified as open surface water to preserve water pixels in region of product granule overlap. The images are provided as GeoTIFF files.<\/span><\/p>

Water (WTR) Layer Description: <\/span>Masked interpreted water classification layer. This represents pixel-wise classification into one of three water classes (not water, open water and inundated vegetation), masks (HAND mask and layover/shadow mask), or no data classes.<\/span><\/p>

Water (WTR) Layer Values:<\/span><\/p>

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