Author– Praveen K Thakur, Sakshi Tripathi, Priyanka Tyagi and Hitendra Padalia

Snow cover and its anomaly assessment is a crucial approach for understanding deviations in seasonal snow conditions and their implications for regional hydrology and climate variability. The North Western Himalayan (NWH) states, especially the Uttarakhand, Himachal Pradesh and Jammu and Kashmir states of NWH region have received very less snowfall for the winter of 2025-26.  Satellite remote sensing remains the major and only source of getting synoptic snow cover area information on regular basis over Himalayan region.

The post-monsoon to early-winter period (October-December) is a critical transitional phase for the onset and persistence of seasonal snow cover vvariability in the NWH. This season snow and rain also controls the soil moisture recharge and forest fuel conditions, which has cascading implications for forest disturbance and wildlife dynamics.

Official meteorological assessments indicate pronounced anomalies during late 2025. According to monthly climate summaries issued by the India Meteorological Department (IMD), October 2025 experienced episodic rainfall associated with synoptic disturbances, with total precipitation of approximately 56.3 mm compared to a climatological normal of 21.6 mm (+161% departure). However, this rainfall was short-lived and unevenly distributed during 1^st week of October 2025. In contrast, November 2025 recorded a substantial rainfall deficit across the NWH region, with only ~2-3 mm of rainfall received against a normal of ~12-15 mm, corresponding to a deficit of approximately 60-70%. This was followed by near-absence of precipitation during December 2025, when only ~2-3 mm of rainfall was recorded against a normal of ~20 mm, indicating a -85% rainfall deficit.

The reduction in post monsoon and winter precipitation has direct impact on water availability and ecological functioning of NWH ecosystems. This snow and rain deficit leads to drier conditions, favouring early-winter forest fires indicating hydro-climatic stress in the Himalayan region. Reduced post-monsoon moisture, delayed snowfall, and warmer early-winter temperatures maintain dry surface fuels and extend the window of fire susceptibility beyond the traditional fire season. Satellite-derived fire detections therefore provide an objective proxy for ecosystem dryness and disturbance.

In this study, snow anomaly over the entire NWH was evaluated for the period 30 November 2025 to 10 January 2026 by comparing observed daily snow cover area (SCA) with a long-term snow cover derived for the period 2000–2025. A long term daily percentage snow occurrence map was generated using historical daily snow cover data, and pixels exhibiting >50–100% snow occurrence were converted into a binary reference snow maps.

The daily snow cover was then compared against this reference to classify snow conditions into deficit, normal, and excess categories. The results show that during late November 2025 and Mid December 2025, Uttarakhand experienced a pronounced dominance of snow deficit conditions (~45-75% between 20 November -30 December 2025), indicating delayed or below-normal snow accumulation, whereas the broader NWH region exhibited relatively higher proportions of normal snow cover (Figure 1a, 1b and 2) mainly due to fresh snowfall in higher reaches of NWH in last week of 2025. Similarly, water level data from CWC (Central Water Commission), indicates gradual and consistent decrease in river flow over majority of rivers in Upper Ganga basin.

Figure 1a and 1b: Satellite derived snow anomaly (30 Nov, 2025 – 10 Jan, 2026) as compared with long-term mean snow cover for Uttarakhand and NWH region.

Figure 2 Snow Anomaly maps of NWH region, 20 December 2025 and 10 Jan 2026.

Towards late December 2025 and early January 2026, both regions showed a gradual transition towards normal snow conditions; however, excess snow cover remained spatially limited throughout the study period, with a slightly higher occurrence over J&K and Ladakh, and Himachal Pradesh states as compared to Uttarakhand. Moreover, the Uttarakhand SCA for the year 2025 remained well below long-term mean SCA, except for few day/weeks during 1^st week of January 2025, Mid Feb 2025 and Late Monsoon and early October 2025 (Figure 3).

Figure 3: Daily snow cover of Uttarakhand as compared with long term mean SCA.

Forest fires as indicators of climatic stress

Similarly, VIIRS active fire detections for October, November, and December 2025 were processed in a GIS environment (QGIS v3.x). The active Fire points were spatially clipped to the Uttarakhand state boundary and separated into monthly datasets based on acquisition date. The resulting datasets reveal strong spatial clustering of early-winter fire activity rather than random distribution, indicating zones of persistent dryness and fuel availability. The fires were concentrated primarily in mid-elevation forest belts, consistent with pine-dominated and broadleaved mixed forest systems known to be highly fire-prone under dry conditions. The fire incidences can also be observed in the high-altitude temperate forests and alpine region particularly towards the extreme eastern part of Uttarakhand (Figure 4).

Linking climatic stress, fires, and wildlife behaviour

Forest fires act as a critical intermediary linking climatic anomalies to wildlife stress and displacement. Burning of forest understory and litter reduces the availability of natural forage such as berries, roots, and invertebrates, while also degrading shelter and cover. For Himalayan black bears, which rely on late-season food accumulation prior to denning, such losses can create energetic deficits. The Himalayan black bears undergo hibernation during the cold winter time. However, the warmer early-winter temperatures might have delayed the denning behaviour, extending the period of active foraging.

Figure 4: Satellite derived fire density map of Uttarakhand for Oct-Dec 2025

Under these combined conditions like delayed snowfall, dry forest floors, and reduced natural food availability, bears are more likely to descend to lower elevations and human-dominated landscapes in search of alternative food sources. Agricultural fields, orchards, livestock sheds, and areas where fodder and firewood are collected become focal points of interaction, substantially increasing the probability of human-bear encounters. This is highlighted by recent multiple Himalayan black bear attacks on humans as reported in Uttarkashi, Pauri, Chamoli, and Rudraprayag districts during November-December 2025 and early January 2026.

Summary and Outlook

Overall, the analysis highlights pronounced anomalies in early winter snow conditions, with Uttarakhand showing comparatively lower snow accumulation than the NWH during the early phase of the 2025–26 winter season. Further if winter monsoon revises in next few days/weeks of late January 2026 onwards, some of the snow and rain deficit can be overcome, but as winter season is progressing, the new fresh snow may be insufficient to meet seasonal water and moisture of entire ecosystem due to rising temperature, wet snow conditions and increased snowmelt of spring season.

The convergence of post-monsoon rainfall deficits, warmer early-winter air temperatures, delayed snowfall, and increased early-winter forest fires presents a compelling climatic pathway influencing human-wildlife conflict in Uttarakhand. Forest fires serve as a spatially explicit indicator of eco-hydrological stress, linking climate anomalies to ecosystem disturbance and wildlife displacement. In this context, the recent escalation of bear attacks should not be viewed as isolated events but as manifestations of broader climate-mediated landscape stress.

Further readings:

• Thakur P.K., Garg V., Nikam B.R., Aggarwal S.P., Aggarwal S., Singh D. (2021) Snow, Glacier, and Glacier Lake Mapping and Monitoring Using Remote Sensing Data. In: Taloor A.K., Kotlia B.S., Kumar K. (eds) Water, Cryosphere, and Climate Change in the Himalayas. Geography of the Physical Environment. Springer, Cham. https://doi.org/10.1007/978-3-030-67932-3_4.
• Sakshi Tripathi et al., 2025. Long-term Snow Cover Dynamics in the Indian North-Western Himalayas using Multi-Sensor Satellite Data. IAHS XII^th scientific assembly of the International Association of Hydrological Sciences (IAHS 2025), held at IIT Roorkee during 05–10 October 2025.
• Schroeder, W., et al. (2014). The new VIIRS 375 m active fire detection data product: Algorithm description and initial assessment. Remote Sensing of Environment, 143, 85-96.
• Giglio, L., et al. (2018). Satellite-based estimates of fire activity and climate controls. Remote Sensing of Environment.
• India Meteorological Department (IMD). Monthly climate summaries, October-December 2025.
• NASA FIRMS. VIIRS Active Fire Data Portal.
• The Print, 2026. Bear attacks surge in Uttarakhand; Chamoli among worst hit districts.
• Amar Ujala, 2025. Hill districts report rising bear attacks during fodder collection season.
• Government of Uttarakhand, 2025. Proceedings of the 22nd State Board for Wildlife Meeting.