Bitcoin hash rate drops 30% in emergency! US winter storm paralyzes Foundry mining pool

American Storm Causes Foundry Hashrate to Drop from 340 to 242 EH/s (-30%), Block Time Surges to 14 Minutes. Luxor Also Offline 110 EH/s. Texas Miners Participate in ERCOT Load Shedding Program, CleanSpark Cuts Hundreds of Megawatts in Minutes. Geographical and Coordinated Concentration Expose Systemic Vulnerabilities.

Foundry Hashrate Drops 30% from 340 to 242 EH/s

(Source: TheHashrateIndex)

A winter storm sweeping across the United States has revealed the real reason behind the slowdown in Bitcoin mining network speeds, leading to a sharp decline in Bitcoin mining activity. We rarely consider that severe weather can impact Bitcoin’s security, but such situations are actually quite common. Snowfall can indeed pose risks to Bitcoin miners maintaining blockchain security. First, weather forecasts show snow across state lines with large swaths of color. Then, it becomes tangible: power lines sway in the wind, workers stand by, and households struggle to keep warm.

Behind these seemingly normal human scenes lies another set of devices: rows of Bitcoin miners operating when electricity is cheap and plentiful, then sometimes shutting down proactively when grid stress is high. This context explains two nearly simultaneous events: the dramatic change in the US’s largest Bitcoin mining pool Foundry, and the significant drop in network hashrate shown in the charts.

According to TheMinerMag, during the recent cold snap, Foundry’s Bitcoin hashrate fell from a peak of about 340 EH/s to approximately 242 EH/s, a decline of about 30%. The report also mentions that Luxor pool experienced a fault, with over 110 EH/s of capacity taken offline. As of press time, Foundry’s 3-day average market share had dropped to 21.95%, with hashrate at just 185.9 EH/s. Depending on the retrospective window, Foundry’s share of blocks typically ranges between 20% and 30%. Hashrate indices show that over the past three days, Foundry’s share of blocks was around 22%, down from 30% last month.

This 30% decline is a significant event in Bitcoin mining history. Foundry, the world’s largest Bitcoin pool, accounts for roughly a quarter of the global total hashrate. When such a large portion of hashrate suddenly goes offline, the entire Bitcoin network feels the impact. Block production slows, transaction confirmation times lengthen, and network security margins temporarily decrease. Although the Bitcoin protocol’s difficulty adjustment mechanism will automatically lower mining difficulty in the next adjustment period (about two weeks) to restore normalcy, the network remains relatively vulnerable before the adjustment occurs.

Texas Miners’ Load Shedding and Demand Response Programs

Weather impacts electricity demand, which puts pressure on the grid; miners either disconnect or choose to sell power back to the grid. The network perceives a reduction in hash rate per second. In places like Texas, increasingly industrial-scale mining operations behave like interruptible loads. Miners, after signing agreements, can quickly reduce power generation and earn credits, while grid operators can take corresponding measures during peak demand. The U.S. Energy Information Administration (EIA) has discussed how large loads, including cryptocurrency mining, can participate in voluntary load reduction agreements with the Texas Reliability Entity (ERCOT).

From a corporate perspective, this is not hypothetical. According to DataCenterDynamics, CleanSpark responded to TVA’s request by reducing hundreds of megawatts across multiple sites within minutes. This capability appears as a cliff on the chart because it essentially is a cliff. That’s why even if you’ve never seen miners in snow piles, there can be a connection between a major storm and a sudden drop in Bitcoin hashrate. Axios reports that during storms, systems like ERCOT and PJM face stress risks.

This demand response mechanism is a win-win for the grid: the grid gains additional power during emergencies, and miners are compensated for curtailing power. But for the Bitcoin network, this means hashrate can fluctuate dramatically due to external factors at any time. When grid stress occurs, hundreds of megawatt-scale mining farms could shut down simultaneously within minutes, causing a cliff-like drop in hashrate. This systemic vulnerability is a direct consequence of the geographic and coordinated centralization of Bitcoin’s hashrate.

Dual Centralization of Geography and Coordination Exposes Systemic Risks

Mining systems have two key concentrations under stress: geographic concentration and coordination concentration. Geographic concentration means many machines are located under the same sky, exposed to the same cold front, ice sheet, and managed by the same grid operator. Coordination concentration means many machines point to the same pool, making the public dashboard feel like a single organism. When both conditions are met, weather can trigger sudden and significant fluctuations in hashrate.

Foundry exemplifies these two concentrations perfectly. Geographically, most of its hashrate comes from the US, especially Texas and other energy-rich states. These regions are often affected by the same weather systems. In terms of coordination, Foundry, as a single pool, coordinates about 25% of the global Bitcoin hashrate. When winter storms hit the US, they impact both Foundry’s large geographic footprint and the entire coordinated network, causing a concentrated and pronounced drop in hashrate.

This centralization challenges Bitcoin’s decentralization ideals. Bitcoin is designed as a decentralized monetary system, where no single entity or region can control the network. But when a single pool controls 25% of the hashrate, and that hashrate is highly concentrated in one country, weather, policies, or infrastructure issues in that region can significantly affect the global Bitcoin network. This starkly reveals the gap between the ideal of decentralization and the current reality.