Bitcoin Hashrate Plummets: Understanding the Impact of Weather and Miner Behavior
The resilience of Bitcoin is often touted, but rarely do we consider how external factors, like severe weather, can directly impact its security. Surprisingly, snowstorms and extreme temperatures can pose a legitimate risk to the network, affecting Bitcoin miners who are crucial for securing the blockchain. This isn't a theoretical concern; recent events, including a significant shift at Foundry, the largest US mining pool, and a broad dip in network hashrate, highlight this vulnerability. This article delves into the connection between weather events, mining operations, and the overall health of the Bitcoin network, providing a comprehensive analysis of the current situation and its potential implications.
The Interplay Between Weather, Power Grids, and Bitcoin Mining
When a major winter storm hits the US, the immediate concerns are power outages and the safety of communities. However, behind the scenes, a less visible impact unfolds on the Bitcoin network. A growing number of industrial-scale mining operations, particularly in regions like Texas, operate as interruptible loads. This means they have agreements to curtail their power consumption quickly when the grid is under stress, effectively selling power back to the grid during peak demand. This flexibility is beneficial for grid stability but introduces a point of vulnerability for the Bitcoin network.
How Curtailment Affects Hashrate
When miners curtail operations or experience power outages due to weather events, the network's hashrate – the total computational power dedicated to securing the blockchain – decreases. While daily hashrate estimates on dashboards like BitInfoCharts aren't direct readings of machines, they are inferred from blocks found over time. These estimates can be noisy, with short windows showing fluctuations even without changes in the real world. A one-day drop is a clue, but not a definitive conviction. A more reliable indicator is a sustained decrease observed over a 7 or 14-day average, as noted by providers like Blockchain.com.
Recent data showed a notable dip in hashrate, with some reports indicating a nearly 10% decrease. This coincided with a period of slower block production, with average block times stretching to around 11 minutes, as observed on mempool.space. This suggests that a significant portion of mining capacity was indeed offline, not simply redistributed among pools.
Foundry's Shift and the US Mining Landscape
Foundry, as the largest Bitcoin mining pool in the US, holds significant sway over block production, often controlling between 20% and 30% of the network's hashrate. Recent data from the Hashrate Index shows Foundry’s share has fluctuated, currently around 22% over the past 3 days, down from 30% over the month. A sharp move in Foundry’s hashrate often sparks broader conversations about the stability and decentralization of the network.
During the recent cold snap, reports indicated Foundry’s hashrate fell from approximately 340 EH/s to around 242 EH/s, a drop of roughly 30%. Luxor also experienced a significant offline period, with over 110 EH/s taken offline across both pools. As of January 26, 2026, Foundry's 3-day average market share has fallen to 21.95% with its hashrate at just 185.9 EH/s. This decline is particularly noteworthy because Foundry often serves as a proxy for US mining behavior. When a large portion of US-based mining capacity is concentrated in a region experiencing severe weather, a storm can have a cascading effect on the network.
The Role of Grid Operators and Curtailment Programs
Grid operators, like ERCOT and PJM, often telegraph potential stress windows during extreme weather events. They may implement emergency measures and consider backup generation. The US Energy Information Administration (EIA) has discussed the participation of large loads, including crypto mining, in voluntary curtailment arrangements. Companies like CleanSpark have demonstrated the ability to curtail hundreds of megawatts within minutes in response to grid operator requests, showcasing the speed and responsiveness of these operations.
The Macroeconomic Context and Miner Behavior
The impact of weather-related curtailments extends beyond immediate hashrate fluctuations. Miners who are forced to reduce operations experience a drop in revenue while fixed costs remain constant. This necessitates difficult decisions regarding treasury management. Some miners may monetize power markets, others may sell Bitcoin, and some may do both. Recent actions by Riot Blockchain, selling 1,818 BTC in December 2025 for $161.6 million, and CleanSpark, reporting similar sales activity, illustrate this trend.
A storm-driven curtailment window can trigger a cash-flow event, forcing miners to reassess their financial strategies. Those with access to curtailment credits are better positioned to weather the storm, while others may rely more heavily on Bitcoin sales. This dynamic highlights the financial pressures facing miners and the potential for increased market volatility.
Geographic and Coordination Concentration: A Recipe for Volatility
The Bitcoin mining system is susceptible to two key types of concentration that amplify the impact of stress events: geographic concentration and coordination concentration. Geographic concentration means a large number of mining machines are located in the same area, exposed to the same weather conditions and grid vulnerabilities. Coordination concentration refers to a significant portion of those machines being connected to the same mining pool. When both are true, weather events can trigger a sudden and visible hashrate shock.
Implications for Bitcoin Holders and Network Security
The recent events serve as a reminder that even a network often described as "unstoppable" is still reliant on real-world infrastructure and susceptible to external factors. A decrease in hashrate can lead to slower block times and potentially higher transaction fees, although the impact on fees depends on network demand. More importantly, these events raise questions about the resilience and decentralization of the Bitcoin network.
Technical Consequences: If miners go offline, block times slow until difficulty adjusts. Higher demand during slower block times can lead to increased fees.
Economic Consequences: Miners may sell Bitcoin to cover costs during curtailment periods, potentially impacting market prices.
Narrative Consequences: Significant shifts in large US-linked pools raise concerns about centralization and the control of block production.
Looking Ahead: The Future of Bitcoin Mining and Grid Integration
The trend towards locating mining operations in regions with flexible and market-based power access is likely to continue. This will inevitably lead to increased interaction with grid operators and a greater potential for curtailment during extreme weather events. The key to mitigating these risks lies in fostering greater grid resilience, incentivizing miners to participate in demand response programs, and promoting a more geographically diverse mining landscape.
The forward-looking takeaway is simple: extreme weather is becoming a recurring stress test for US mining, and US mining has become a stress test for Bitcoin’s visible decentralization story. If miners continue to lean into grid programs, expect more short-lived hashrate cliffs during heat waves and freezes. If hashrate continues to trend upward, the cliffs may get sharper when margins are tight. That is where treasury behavior starts to matter, as shown by Riot and others.
The next storm will be a systems story, not just a weather story. That is what makes this interesting, even when the hashrate line bounces back a day later.
Mentioned in this article
Bitcoin
Foundry
Luxor
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