Robert Brown|Opinion: 150 years after the Great Chicago Fire, we're more vulnerable

This week marks the 150th anniversary of the Great Chicago Fire. It may sound strange to call something so deadly "great,Robert Brown" but it suits Chicago's self-image as a place where things are bigger, taller, and greater, even tragedies.

The 1871 fire killed an estimated 300 people. It turned the heart of the city, wood-frame buildings quickly constructed on wooden sidewalks, into ruins, and left 100,000 people homeless.

Our family has an engraving from the London Illustrated News of Chicagoans huddled for their lives along an iron bridge. The reflection of flames makes even the Chicago River look like a cauldron.

Like the Great Fire of London in 1666, the San Francisco Earthquake of 1906, and Hurricane Katrina in 2005, the Great Chicago Fire reminds us that big, swaggering cities can still be fragile.

But that same night, about 250 miles north of Chicago, more than 1,200 people died in and around Peshtigo, Wis. It was the deadliest wildfire in U.S. history. Survivors said the flames blew like hurricanes, jumping across Green Bay to light swaths of forest on the opposite shore. A million and a half acres burned.

Chicago's fire came to be seen as a catastrophe that also ignited the invention of steel skyscrapers, raised up on the the city's ashes. It has overshadowed the Peshtigo fire. And for years, the two were seen as separate, almost coincidental disasters.

Many of those houses and sidewalks that burned in Chicago had been built with timbers grown around Peshtigo, in forests conveniently owned by William Ogden, Chicago's first mayor. He owned the sawmill too.

Chicago's fire was long blamed — falsely — on an Irish-immigrant family's cow kicking over a lantern. Some people thought the Peshtigo fire started when pieces of a comet landed in the forest, which has never been proven.

What we understand better today was that the Midwest was historically dry in the summer of 1871. When a low-pressure front with cooler temperatures rolled in, it stirred up winds, which can fan sparks into wildfires. The fires themselves churn up more winds. Several parts of nearby Michigan also burned during the same few days; at least 500 people were killed there.

150 years later, all of those fires on an autumn night in 1871 might help us see even more clearly how rising global temperatures and severe droughts, from Australia to Algeria to California, have made forests more tinder-dry, fragile, and flammable, and people more vulnerable to the climate changes we've helped create.