<div class="callout">Executive SummaryIn December 2025, Skagit County, Washington experienced severe flooding triggered by an Atmospheric River event. This analysis focuses on the Skagit River corridor near Burlington and Mount Vernon.<dfn data-content="A radar imaging technology that uses microwave signals to observe the Earth’s surface regardless of cloud cover or precipitation, enabling rapid assessment of heavy rainfall and flood damage.">Synthetic Aperture Radar (SAR)</dfn> imagery was utilized to quantify inundation extent under cloud-covered conditions.The results provide objective measurements of flood-affected areas, vulnerable zones, and agricultural impacts.</div>In early December 2025, Skagit County experienced intense short-duration precipitation driven by an <dfn data-content="A meteorological phenomenon in which a long and narrow corridor of concentrated water vapor, formed over tropical or subtropical oceans, transports large amounts of moisture toward mid-latitude regions and generates intense and prolonged precipitation.">Atmospheric River</dfn> system. River levels rose rapidly, prompting upgraded flood warnings and evacuation alerts.<blockquote class="corner-blockquote">Comprehensive Analysis of Flood Damage in Washington State</blockquote>Atmospheric River events can deliver months’ worth of rainfall within several days, often resulting in widespread flooding. Given the increasing frequency of extreme precipitation events, this study extends beyond temporary inundation mapping and identifies concentrated damage zones and recurring risk segments through satellite-based analysis.<blockquote class="blockquote">Skagit River Waterbody Area Change</blockquote>This analysis focuses on the Skagit River main channel, excluding adjacent reservoirs including Shannon, Baker, and Diablo Lakes.Optical imagery is often limited immediately after flood events due to cloud cover and rainfall. Therefore, SAR imagery acquired on November 29, 2025 (pre-flood) and December 11, 2025 (post-flood) was used to detect waterbody expansion and calculate inundation extent.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-251129-washington-state-skagit-county-skagit-river-waterbody-area-change-analysis.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-251211-washington-state-skagit-county-skagit-river-waterbody-area-change-analysis.png" class="image-slide-preview"></div>The total waterbody area increased from 15.96 km² before flooding to 18.81 km² after flooding. Expansion was concentrated along meander bends rather than straight river segments. Outer low-elevation banks along curved sections experienced significant widening, in some cases extending beyond prior channel boundaries. Straight sections showed comparatively limited lateral expansion.<img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-river-detailed-analysis-areas.png" class="default-image-preview">These characteristics become more evident when the river is examined by sub-region.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-burlington-skagit-river-waterbody-area-before-flood.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-burlington-skagit-river-waterbody-area-after-flood.png" class="image-slide-preview"></div>In the Burlington area, waterbody extent increased from 1.1 km² to 1.4 km².<img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-burlington-skagit-river-flood-damage-assessment.png" class="default-image-preview">The geometric expansion was relatively limited, but adjacent agricultural land shows potential exposure risk.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-lyman-skagit-river-waterbody-area-before-flood.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-lyman-skagit-river-waterbody-area-after-flood.png" class="image-slide-preview"></div>In the Lyman area, waterbody extent increased from 2.2 km² to 3.0 km².<img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-lyman-skagit-river-flood-damage-assessment.png" class="default-image-preview">The narrow channel width and frequent meanders amplified outward expansion along outer-bank lowlands.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-concrete-skagit-river-waterbody-area-before-flood.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-concrete-skagit-river-waterbody-area-after-flood.png" class="image-slide-preview"></div>In the Concrete area, waterbody extent increased from 2.4 km² to 3.1 km².<img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-concrete-skagit-river-flood-damage-assessment.png" class="default-image-preview">Expansion patterns were concentrated along curved river sections, similar to those observed in the Lyman area.The combined increase across these three areas reached 1.8 km², accounting for approximately 63 percent of the total river expansion of 2.85 km². This confirms that flood expansion was spatially concentrated rather than evenly distributed.<blockquote class="blockquote">Agricultural Inundation Impact Analysis</blockquote><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-agricultural-area-classification.png" class="default-image-preview">Flooding affects not only surface water dynamics but also land value and agricultural productivity. Agriculture represents a core economic sector in Skagit County, making precise impact assessment essential.Agricultural land west of Burlington and Mount Vernon was divided into northern and southern zones for detailed parcel-level analysis.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-northern-agricultural-area-flood-damage.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-northern-agricultural-area-flood-damage-parcel-classification.png" class="image-slide-preview"></div>Out of 1,147 agricultural parcels, 252 parcels were inundated, representing approximately 22 percent impact rate. Flooding spread in continuous bands along floodplain corridors and drainage-prone pathways, indicating topographic susceptibility to water retention.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-southern-agricultural-area-flood-damage.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-southern-agricultural-area-flood-damage-parcel-classification.png" class="image-slide-preview"></div>Out of 2,265 agricultural parcels, 270 parcels were inundated, representing approximately 12 percent impact rate. In contrast to the north, inundation occurred in more fragmented patterns rather than continuous belts.Assessing crop losses caused by flooding supports economic decision-making, including estimating compensation ranges for farmers and establishing crop selection strategies that account for <dfn data-content="Long-term exposure of agricultural production to climate variability such as extreme rainfall, drought, or temperature anomalies, which may affect yield stability and financial performance.">climate risk</dfn>. An analysis of cultivation patterns shows that corn and potatoes are the two dominant crops by cultivated area in both the northern and southern agricultural zones.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-northern-agricultural-area-crop-cultivation-before-flood.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-northern-agricultural-area-crop-cultivation-after-flood.png" class="image-slide-preview"></div>In the northern agricultural area, corn experienced the most severe impact. Of the total 9.6 km² under corn cultivation, 7.2 km² was inundated, representing approximately 74 percent of the planted area. In comparison, 3.4 km² of the 7.9 km² devoted to potato cultivation was affected.<div class="image-slide"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-southern-agricultural-area-crop-cultivation-before-flood.png" class="image-slide-preview"><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-southern-agricultural-area-crop-cultivation-after-flood.png" class="image-slide-preview"></div>In the southern agricultural area, 5.8 km² of the 12.25 km² planted with corn was inundated, while 3.92 km² of the 23.3 km² planted with potatoes experienced flood damage. As the primary crops with the largest cultivation areas, both corn and potatoes were directly exposed to inundation, leading to productivity contraction in both northern and southern agricultural zones. However, even for the same crop, impact ratios differed depending on crop distribution patterns and local topographic conditions.<blockquote class="blockquote">Flood Risk Map of Skagit County, Washington</blockquote><img src="https://earthpaper.s3.ap-northeast-2.amazonaws.com/post/v2/editor/38/en-2025-washington-state-skagit-county-flood-risk-map.png" class="default-image-preview">Flood risk levels were calculated using a weighted combination of cumulative precipitation, terrain slope and flatness, and proximity to the regional <dfn data-content="An integrated hydrological framework in which rivers, tributaries, lakes, reservoirs, and wetlands within a watershed are physically interconnected through continuous surface or subsurface water flow and storage processes.">water system</dfn>. Medium- to high-risk zones form broad, continuous bands along the Skagit River corridor, indicating elevated potential for recurrent inundation across Skagit County. The spatial distribution of medium- and high-risk segments suggests that certain areas require heightened attention in future land-use planning and insurance underwriting decisions.This analysis extends beyond simple flood damage quantification. It provides an integrated assessment of land and crop loss, topographic vulnerability, and zones with a high likelihood of repeated flood exposure.<div class="callout">Satellite Imagery Analysis SolutionSeeking comprehensive climate risk management support?Satellite-based analytics deliver objective insights ranging from immediate damage quantification to recurring flood risk diagnostics.<a target="_blank" rel="noopener noreferrer nofollow" href="https://ep.naraspace.com/helpcenter/inquiry">For consultation, please contact our team.</a></div>

2025 Washington State Flood Damage Satellite Analysis: Skagit River Area Expansion and Agricultural Inundation Impact

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