US storm slashes BTC hashrate 60%

TLDR

A powerful US winter storm has forced major Bitcoin miners offline, temporarily cutting hashing power and slowing blocks but not fundamentally breaking Bitcoins security.

1. Foundry USA, the largest BTC mining pool, reportedly cut its hashrate by about 60% amid the storm, stretching block times to around 12 minutes.
2. The broader network hashrate is down meaningfully but far less than 60%, and difficulty will auto-adjust if conditions persist, helping normalize block times.
3. Key things to watch are storm duration, network hashrate recovery, fees and congestion, and longer term pressure on miners from energy markets and competing power users like AI.

Confidence: high because multiple independent reports describe consistent hashrate drops and block-time effects.

Deep Dive

1. What Actually Dropped

Reports say Foundry USA, the largest Bitcoin mining pool, reduced its hashrate by nearly 200 EH/s, about a 60% cut from its recent level, due to winter storm Fern in the United States, slowing blocks to roughly 12 minutes on average instead of the usual 10 minutes for a period of time.Foundry USA hashrate down 60%

Other coverage notes that while Foundry and peers curtailed heavily, the total Bitcoin network hashrate has fallen on the order of 10-20% from recent highs, not 60%, with the 7-day average slipping under 1 ZH/s for the first time since late 2025.Bitcoin hashrate drops below one zettahash

2. Why Storms Hit BTC Mining

The storm has created extreme cold, grid strain, and widespread power outages across large parts of the US, prompting miners to voluntarily power down to free electricity for households and critical infrastructure.Winter storm pressures US miners

Bitcoin miners are often treated as flexible load: they soak up cheap surplus power in normal times and shut off quickly when grid operators need capacity, which is why US storms cause sharp but reversible drops in hashrate.

3. Network Security And What To Watch

Even with a double digit percentage drop in hashrate, Bitcoins proof-of-work remains secure, but lower hashrate slightly increases theoretical attack feasibility and temporarily slows confirmations until difficulty adjusts downward at the next adjustment window.

Users and miners should watch: 1) average block interval (near or above 10 minutes), 2) fee levels and mempool congestion during the storm, and 3) the next difficulty change, which is expected to be a negative adjustment if reduced hashrate persists.Bitcoin difficulty expected to decline

Longer term, competition for cheap power from AI and data centers, plus increasing weather-related curtailments, may push mining toward more efficient operators and regions with steadier energy supply.

Conclusion

The US storm has triggered a sharp, pool-level hashrate cut of about 60% at Foundry USA and a notable but smaller drop in total Bitcoin hashrate, briefly slowing blocks and tightening capacity. As weather and grids stabilize and difficulty adjusts, the network should mechanically rebalance, but the episode highlights how concentrated, weather-sensitive power grids and rising competition for electricity can shape Bitcoins mining landscape over time.