These 2 US cities are the most vulnerable to solar storms, scientists say

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As we approach solar maximum — the most active period in the solar cycle — it's no surprise that scientists are looking into the effects of geomagnetic storms on Earth. While increased solar activity often leads to brilliant showings of auroras, it also can wreak havoc on our technological systems here on Earth.

We most commonly see interference in radio transmissions during strong geomagnetic storms,  but geomagnetically induced currents (GICs) have been known to take out power lines and transformers, too. A team from the British Geological Survey (BGS) has evaluated the vulnerability of cities' power grids and determined that two American cities are especially at risk during a geomagnetic storm: Milwaukee and Washington, D.C.

Lauren Orr of the BGS suggests various reasons as to why these two cities are particularly vulnerable, including "electrical conductivity of the ground, the physical construction of the power grid in those areas, or the location of the auroral currents in the sky."

Now, this isn't a red-alert emergency yet — most solar storms we've experienced in the last 100 years haven't been strong enough to wipe out a power grid. But if something like the 1859 Carrington Event, the strongest recorded solar storm in history, were to happen again, the problems would be severe.

Orr therefore posits that we should monitor cities like Milwaukee and Washington, D.C., to further learn what can be done to protect their power grids.

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"Network science is now a common tool to quantify the resilience and robustness of power grids to both deliberate attacks and those caused by random failures or natural disasters," she said in a statement. "Having previously had great success using network science to uncover patterns within the auroral electrojet, we would again combine the fields of network science and space weather to capture the network response to GICs."