Bitcoin hashrate plummets, diminishing security as a leading mining pool loses 30% of its capacity.

One aspect that often escapes our thoughts is how adverse weather can impact the security of Bitcoin, yet this occurrence is relatively common. Snow can genuinely present a threat to Bitcoin miners who maintain the blockchain’s integrity.

The snow first appears on the weather map as a broad streak of color spanning state boundaries. Subsequently, it transitions into tangible effects: power lines swaying in the wind, crews on alert, households striving to maintain warmth.

Beneath that ordinary human scenario lies a different type of machinery: rows of Bitcoin miners that operate when electricity is abundant and inexpensive, but may intentionally cease operations when the grid faces strain.

This sets the stage for two events that occurred closely together and could be misinterpreted if one only examines the headline statistics: a significant shift at the largest Bitcoin mining pool in the US, Foundry, and a widespread decrease in network hashrate that was reflected in the charts.

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The hashrate decrease that is visible to all

If you monitor mining data regularly, you likely noticed the same trend: hashrate suddenly dropping, accompanied by a significant red percentage next to it.

BitInfoCharts, a chart frequently captured and shared by many, indicated a remarkable 24-hour decline in its daily estimate as of the time of this writing. This is where the “almost 10%” discussions originate, and the fluctuation can appear even more pronounced depending on the exact time you check.

Bitcoin hashrate drip (Source: Bitinfocharts)

The initial point to remember is that “hashrate” on these dashboards seldom reflects a direct measurement of machines. It is an estimate derived from blocks discovered over a specific timeframe.

This may seem technical until you recall how Bitcoin operates. Blocks emerge in clusters followed by dry spells, even when external conditions remain unchanged.

Providers such as Blockchain.com have long observed that brief intervals can be erratic for this precise reason, and utilizing a 7 or 14-day average often yields a less sensational perspective.

Thus, a one-day decrease serves as an indication. It is not definitive.

Bitcoin 7-day average hashrate (Blockchain.com)

When the decline is genuine, you typically observe it elsewhere as well. Block times extend, difficulty estimates fluctuate, and the mempool may begin to feel constrained if demand exists.

Indeed, on the day in question, mempool data indicated slower block production, with average block time readings around the 11-minute mark in a snapshot view on mempool.space.

However, that kind of reading does not independently confirm a specific percentage drop. Yet it aligns with a period when a portion of mining capacity is genuinely offline, rather than merely shifting among pools.

The storm, the grid, and the aspect people overlook

Now we reintroduce the human element: the US is approaching a significant winter weather event.

AP’s reporting outlined a substantial storm setup with widespread effects and many customers losing power in certain areas.

When such storms strike, the grid becomes the focus, not Bitcoin. It is easy to perceive miners as mere observers.

In the US, they are frequently woven into the narrative.

A growing segment of industrial-scale mining in areas like Texas functions as an interruptible load. Miners enter into agreements; they can curtail quickly, earn credits, and grid operators possess a mechanism to activate during demand surges.

This concept is also reflected in government terminology. The US EIA has discussed large loads, including crypto mining, participating in voluntary curtailment arrangements with ERCOT.

From the corporate perspective, the speed is not hypothetical.

CleanSpark has reported curtailing hundreds of megawatts across various sites within minutes in response to a TVA request, as covered by DataCenterDynamics.

This capability can manifest on a chart as a drop, because it is indeed a drop.

This illustrates why a significant storm and an abrupt hashrate drop can be interconnected, even if you never observe a miner stuck in a snowdrift.

Weather influences demand. Demand puts pressure on the grid. Miners either lose power or opt to sell power back to the grid.

The network experiences it as fewer hashes per second.

There is another dimension as well: grid operators frequently signal the stress periods.

Axios’s coverage highlighted the strain risk across systems like ERCOT and PJM during the storm timeframe.

Local reporting has also indicated emergency measures and backup generation being contemplated, including coverage from the Houston Chronicle on actions taken in response to extreme cold.

Here is where we need to clarify the narrative without exaggerating. Storms create the conditions for curtailment and outages.

Curtailment and outages can lead to a genuine decline in hashrate. The reduction can be reflected as slower blocks and a decrease in daily hashrate estimates.

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Foundry, and the significance of this one pool

Foundry serves as a focal point in mining discussions because it is large, US-connected, and coordinates a substantial portion of block production.

Depending on the timeframe considered, Foundry’s block share often fluctuates between the high 20s to low 30s. The Hashrate Index currently places it at around 22% over the past three days, down from 30% over the previous month.

Bitcoin mining pools (Source: Hashrate Index)

When Foundry experiences a significant shift, it ignites discussions that extend well beyond Foundry itself.

During the latest cold snap, reporting from TheMinerMag indicated that Foundry’s hashrate fell from approximately 340 EH/s at a peak to about 242 EH/s, a decrease of around 30%.

It also mentioned Luxor dropping, with more than 110 EH/s going offline across those two pools.

As of the latest update, Foundry’s three-day average market share has declined to 21.95%, with its hashrate now at just 185.9 EH/s.

Top Bitcoin mining pools (Source: TheHashrateIndex)

The significance of this is that Foundry can act as a barometer for US mining behavior.

If a substantial amount of US-based capacity is clustered within the same weather system, linked to the same power market logic, and coordinated through a few major pools, a storm does not merely impact one entity.

It affects the entire corridor.

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The risk that is significant

This is where we transition from the daily fluctuations to something more tangible.

The mining system exhibits two forms of concentration that are crucial during times of stress: geographic concentration and coordination concentration.

Geographic concentration refers to many machines operating under the same sky, subject to the same cold front, the same ice, and the same grid operator alerts.

Coordination concentration indicates that numerous machines direct their efforts toward the same pool, causing the public dashboard to behave as if it is a single entity.

When both conditions are met, weather can trigger a sudden and noticeable hashrate shock.

Even if the broader network does not suffer a 30% loss, the public observes a significant pool fluctuation, which carries its own implications.

The technical implications are clear. If miners genuinely go offline, block production slows until difficulty adjusts.

The economic ramifications depend on demand. If block production slows while the mempool is active, fees increase.

If block production slows and the mempool is quiet, the fee impact is less pronounced.

Currently, the “active mempool” scenario is not assured.

Recommended fee levels have occasionally remained low on mempool.space, allowing you to view fee impact as conditional, reliant on whether demand surges during a supply shock.

The narrative consequence is more significant. Each time a major US-connected pool experiences a sharp movement, inquiries arise regarding resilience, decentralization, and who truly governs block production.

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Miner conduct when the lights flicker

There is another reason storms are significant to mining: they intersect with a quieter narrative regarding miner financials and survival.

If a miner curtails operations for a few hours or a day, revenue declines, while fixed expenses continue. Management must determine the appropriate course of action.

Some miners will capitalize on power markets, some will liquidate Bitcoin, and some will pursue both options, with those decisions reflected downstream.

Riot’s updates serve as a useful illustration of how proactive treasury management has evolved.

Riot disclosed the sale of 1,818 BTC in December 2025 for $161.6 million in net proceeds, as noted in the company’s own release at Riot.

CleanSpark also reported sales activity in its updates, with industry coverage summarizing those figures, including Blockspace.

This is crucial because a storm-induced curtailment period can transform into a cash-flow event.

If miners can gain credits by shutting down, they have a buffer. If not, they may rely more heavily on treasury sales.

We all recognize the outcome when the income clock halts, but the expenses do not.

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The macro layer, why this continues to resurface

Storms are episodic. The system design is ongoing.

Mining has been gravitating toward regions with abundant, flexible, and market-driven power. This often necessitates proximity to grids that can request curtailment during demand spikes.

This is part of why US mining has become both influential and vulnerable.

Commentary from mining analytics firms has also underscored winter energy dynamics and curtailment as a recurring factor behind hashrate weakness, as noted by HashrateIndex.

JPMorgan’s perspective highlights the other side: when hashrate declines, profitability for the remaining miners can improve.

This creates a perverse incentive loop where some miners gain benefits from others being forced offline.

Furthermore, longer-term forecasts place greater emphasis on the supply side: more hashrate coming online over time, increased competition for megawatts, and greater pressure on margins.

Hashlabs, for instance, has projected a range of end-2026 hashrate outcomes, with estimates around the 1.7 ZH/s mark depending on the assumptions made.

Storms hit harder in a low-margin environment.

When miners have flexibility, they can absorb downtime. When they are squeezed, every curtailment period becomes a financial decision.

So, is the storm connected to the hashrate decline?

The straightforward answer is: yes, it could be.

You can construct a plausible argument without claiming to possess a meter on every ASIC in the country.

A strong correlation appears as follows: storm alerts intensify, grid operators prepare, outages proliferate, miners curtail or lose power, network block times increase, difficulty expectations decrease, daily hashrate estimates drop, and significant pools with US ties exhibit a visible decline.

We have several elements in play: storm severity and outages reported by AP, grid-stress framing from Axios, and curtailment capability and incentives detailed by the EIA and DataCenterDynamics.

We also have Foundry’s reduction during frigid conditions.

What we should be cautious about is treating the most striking 24-hour statistic as the complete narrative.

Daily hashrate charts are informative. They are also volatile, and that caution is acknowledged by Blockchain.com.

How this affects everyday holders

The underlying theme is the notion that a network often deemed unstoppable is still connected to the same chaotic world as everyone else.

Bitcoin operates on mathematics, but it also depends on electricity. Electricity is influenced by weather, politics, and infrastructure that can fail.

As a storm approaches the US, families stockpile batteries, utilities position vehicles, and miners determine whether to continue hashing or cash in their flexibility.

Amid all this, the blockchain keeps functioning, albeit sometimes at a slower pace, and the charts fluctuate like a seismograph.

Foundry’s transition is part of that landscape. It serves as a reminder that mining coordination holds weight, that large pools reflect significant concentrations of power, and that severe weather can convert that concentration into a sudden shock visible from your device.

The broader hashrate decline is the other facet. It acts as the network-level pulse check, prompting a question readers can grasp even if they previously had little interest in hashrate:

How fragile is this system when the weather turns unpredictable?

During the Jan 2026 winter storm, Foundry’s share of the network slipped slightly while the 7‑day smoothed hashrate showed a local dip (~951 EH/s). Difficulty edged lower through the window, and the theoretical block time, calculated from hashrate and difficulty, briefly spiked above 14 minutes.

Where this leads next

The forward-looking conclusion is straightforward: extreme weather is evolving into a recurring stress test for US mining, and US mining has become a stress test for Bitcoin’s apparent decentralization narrative.

If miners continue to engage with grid programs, anticipate more abrupt drops during heat waves and cold snaps.

If hashrate maintains a long-term upward trend, the drops may become steeper when margins are narrow. This is where treasury management practices come into play, as illustrated by Riot and others.

The next storm will be a systems issue, not merely a weather concern.

That is what makes this topic compelling, even when the hashrate line rebounds a day later.

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