Tag Archives: building codes

Outthink Wildfire—a Podcast Conversation

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It is evident with each increasingly serious and increasingly long wildfire season in the West and South that American still has serious public policy work to do in confronting this hazard. Recently, the National Fire Protection Association unveiled its new policy initiative, Outthink Wildfire, aimed at highlighting the need to move beyond current reactive strategies to widespread adoption and enforcement of building codes, adoption of wiser land-use regulations, and building substantial public pressure to make changes happen quickly.

The American Planning Association has released a new episode in the Resilience Roundtable series of podcasts, sponsored by the APA Hazard Mitigation and Disaster Recovery Planning Division, in which I interview Michele Steinberg, Wildfire Division Manager at NFPA, about this initiative and what results it may produce in reducing wildfire hazards.

Click here to listen to the podcast.

Jim Schwab

Truly Hard Wind

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What in the U.S. Midwest would spur comparisons to a hurricane? What could spread damage over an equally wide area? It is a good bet that most people are unfamiliar with the word “derecho,” which comes from Spanish, meaning “straight,” but such a storm made itself felt just three weeks ago in Iowa, Illinois, and Indiana, as well as parts of Nebraska and Wisconsin. The Spanish word with an adopted meaning in English refers to such a storm’s powerful straight-line winds, as opposed to another adapted Spanish word, “tornado,” literally meaning “turned,” which, of course, refers to a cyclonic, or spinning, meteorological phenomenon.

The Event

On August 10, a derecho took shape in eastern Nebraska and the southeastern corner of South Dakota early in the morning. The city of Omaha suffered some of the initial damage, with an estimated 57,000 people losing power. But as it roared across the center of Iowa, the storm, as derechos often do, rapidly gained wind speed until estimated winds of 140 miles per hour struck Cedar Rapids and surrounding Linn County in eastern Iowa. Nearby Iowa City, home of the University of Iowa, also suffered extensive damage. Derechos can and typically do strike with little warning, unlike hurricanes, but even at speeds of 90 to 100 mph, in this case, it still takes hours to cross Iowa from west to east, and even longer to reach Illinois and Indiana.

Thus, my first warning of what was to come, sitting here in Chicago, was a telephone alert from the University of Iowa around noon that day. I get such alerts because I am on the faculty, although I now teach remotely as an adjunct. But our landline and my cell phone are on the system, so the alerts come automatically. Fortunately, that gave me most of the afternoon to prepare for what was coming, which arrived in our area around 3:45 p.m. Winds and rain pounded on our skylights for nearly 45 minutes, leaving numerous branches and twigs on the ground from our stately American elm, which towers above our house and garage and has probably withstood other storms for at least a century. It was already huge when we built our house in 1994, and we chose to make it sure it remained. Even this storm caused it only minor damage.

The same could not be said of many street trees in parts of Chicago. Trees often collapsed on top of parked cars, leaving many owners to bemoan what became of their vehicles—or, in some cases, the roofs of their homes.

Even the repose of the dead was not left undisturbed. Graceland Cemetery, one of the more famous in Chicago, faces months of repairs and replanting and is closed for six weeks. The storm uprooted about 40 trees and damaged numerous gravestones and monuments. It had become a popular place for peaceful strolls and contemplation during the months of coronavirus-induced shutdown. After the storm, it was a visual mess that will cost about $250,000 to repair.

Removing damaged trees in Chicago’s Rogers Park.

One lesser-known by-product of derechos is tornadoes, which can be spun off from the shelf cloud as it moves through an area. In Chicago, two tornadoes, one EF-1 in the Rogers Park neighborhood along Lake Michigan near the city line with Evanston, literally buzzsawed trees in an area of densely built multifamily housing and small

Insurance claims agents inspect building damage in Rogers Park.

businesses. A few days later, I visited the area to shoot photos that appear here. At first, driving up Greenwood Avenue, I wondered where the damage was. But as I drove further north and approached W. Jarvis Ave., the answer became starkly obvious. I could not drive beyond that corner because the street was blocked; Jarvis was one way going east, but Jarvis east of Greenwood was also blocked. City trucks were removing damaged trees. After finding a way to park without impeding traffic, I encountered insurance agents on the ground shooting outside photos of nearby buildings, presumably for damaged masonry. Any damaged cars had already been removed.

That tornado, and another that reportedly skipped across the Eisenhower Expressway (I-290) on the West Side, dramatically demolished for some an old urban myth that tornadoes don’t strike urban areas. People believe this for various reasons, including how they think tall buildings disrupt wind circulation, but trust me: I’ve been involved in disaster recovery long enough to know that tornadoes do not discriminate against smaller towns. Rogers Park is very urban. Tornadoes go where they please. This specific tornado eventually skipped out over the lake, becoming a waterspout. But it left its mark.

The storm, by the way, ultimately spun off at least 17 documented tornadoes, mostly in northern Illinois, but a few in Wisconsin and Indiana. All were either EF-1 or EF-0 on the Enhanced Fujita scale. But by far, most of the damage resulted from the straight-line winds themselves, which were often in the range of 90 to 100 mph, with a top measured speed of 126 mph in Atkins, Iowa, making them basically of tornado or hurricane strength. And they sped, over the course of a single afternoon, across all or parts of several states.

By 4:30, the storm had continued its march into northwest Indiana, where it finally petered out. But what happened along the way?

Iowans can attest that it functioned across much of their state like a Category 2, maybe even Category 3, hurricane. Lyz Lenz, a columnist for the Cedar Rapids Gazette, noted in a guest column for the Washington Post four days later that the winds had damaged “more than 10 million acres, or 43 percent, of the state’s corn and soybean crop.” The reduction in harvest in Iowa is likely to be between one-fourth and one-half. The heading on her column referred to the storm as an “inland hurricane” that most people had not heard about. The damage was massive enough to be visible in satellite images.

The damage was not just to crops on the ground, but to hundreds of millions of bushels in storage bins on farms and in commercial storage facilities, according to the Iowa Department of Agriculture. Toppled grain bins were a common site.

Damage to Chinese House roof in Grinnell. Photo by Rachel Bly.

Despite those staggering figures, that was only the beginning. Between Indiana and Iowa, four people died from either falling trees or electrocution, and, in one case, a mobile home tipped over by high winds. Losses of electric power affected approximately 585,000 Iowans, or roughly 20 percent, while 1.9 million lost power in neighboring Illinois. Tree damage in Linn County totaled in the hundreds of thousands, and most buildings suffered anywhere from mild to catastrophic damage. In small towns, like Grinnell, building damage and tree damage to cars was also extensive. Here, I wish to thank Rachel Bly, director of Conference Operations and Events for Grinnell College, for sending me dozens of photographs she shot after the event. Bly, I might note, has a certificate in emergency management from Park University in addition to her MPA from Drake University. The images she shared help convey some reality to the trauma that occurred. Hundreds of other small communities suffered similar impacts. Not surprisingly, Gov. Kim Reynolds issued a state disaster declaration by August 14 for 25 counties, and has sought a federal declaration from President Trump, citing an estimated $4 billion in damages. By August 19, Trump had signed a declaration for Public Assistance (PA) but not Individual Assistance (IA) for Iowa. PA provides aid for restoring public infrastructure, such as roads and bridges and community facilities, while IA provides direct aid to individuals for reasons such as loss of housing.

Power line damage in Grinnell. Photo by Rachel Bly.

Photo by Rachel Bly

Roof seen through the window. Photo by Rachel Bly.

Inside a damaged salon in Grinnell. Photo by Rachel Bly.

 

 

 

 

 

 

 

 

 

Derechos as a Natural Hazard

All this raises the question of what we know about derechos as a wind-related hazard. I will confess that I spent most of my life never having heard the word, let alone understanding what it meant. It is not the most common occurrence, but it certainly ranks among the most destructive. To my surprise, I learned from Wikipedia that the term was coined in 1888 by a German-American scientist, Gustavus Detlef Hinrichs, who had emigrated to St. Louis just before the Civil War. He wrote in the American Meteorological Journal about a storm that struck Iowa in 1877 and described its unique characteristics. Nonetheless, even in the Midwest today, many people are unfamiliar with the term—until they hear it on the news, as they did on August 10 amid storm warnings.  

The gust front “arcus” cloud on the leading edge of a derecho-producing storm system. The photo was taken on the evening of July 10, 2008 in Hampshire, Illinois. Credit: Brittney Misialek. From National Weather Service website.

There are several types of derechos, but the National Weather Service describes a derecho as a “widespread, long-lived windstorm that is associated with a band of rapidly moving showers as thunderstorms.” More specifically, it defines the phenomenon as a swath of damage that “extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph (93 km/h) or greater along most of its length.” In plain English, this is a huge, regional storm, not some localized thunderstorm. It exhibits straight-line winds that can be at least double the minimum in the definition, and the August 10 event involved winds far above 58 mph in most locations. Like all such storms, it is a product of unstable atmospheric systems, in this case typically involving a bow-shaped front in a large squall line.

The storms are typically a mid-latitude phenomenon, making North America and the Midwestern U.S. particularly susceptible, but they occur elsewhere in the world as well, including southern latitudes (southeastern Brazil and Argentina), South Africa, China, and even eastern Europe, where a derecho struck parts of Estonia in August 2010, and near Berlin in Germany in 2002. The August 10 event was not the first one I have witnessed in Chicago—another struck in July 2011 and disabled electric power for nearly a million people—but it was certainly the largest in a long time.

70% of all derechos occur between the months of May-August (the warm season). The other 30% occur during the cool season. From National Weather Service website.

As a mitigation planning response, almost no hazard mitigation plan (produced for FEMA approval as a condition of eligibility for federal hazard mitigation grants) for any state or community east of the Rockies (with the possible exception of Florida) should fail to identify derechos as a potential hazard. Moreover, especially in the Midwest, it may be time for states and communities to reexamine their building codes for wind resistance as a means of limiting future damages from derechos. Finally, it may also be time for many communities to examine more closely their urban forestry programs for adequate attention to hazardous tree management. That does not mean refusing to plant trees or removing them unnecessarily as a mindless precaution. It does mean engaging professional urban foresters in an assessment of the urban tree canopy with an eye to ensuring forest health and removing those trees that are most likely to fail under severe wind pressure. Already, the call has arisen for such reforms in Chicago. It is time for planners, environmentalists, disaster professionals, open space advocates, and concerned citizens to seize the moment while they have the public’s attention.

Jim Schwab

Building Codes Matter

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Ask Anchorage after last Friday’s 7.0 earthquake. Admittedly, this is not the biggest earthquake the area could have suffered. The famous 1964 earthquake registered at 9.2, triggered a tsunami, and killed an estimated 130 people. Still, by and large, things seemed to work as planned.

Ask the mayor. And the governor. Mayor Ethan Berkowitz says building codes and good preparation minimized structural damages. No one died. Berkowitz even stated to PBS that other cities would want to emulate Anchorage “because Anchorage did this right.” Alaska Governor Bill Walker admitted to sometimes grousing about strict building codes but conceded, “Building codes mean something,” stating that his own home suffered only minor water damage.

What worked? According to the same PBS report, “Sterling Strait, a member of the Alaska Seismic Hazards Safety Commission, said the states [Alaska and California] use the International Building Code,” which he deemed the “best available standard for seismic safety.”

This good news comes while some states and jurisdictions, in some parts of the country, still resist more stringent building codes, and when some voters still resent what they view as an imposition, sometimes even after the damage from a hurricane, flood, wildfire, or earthquake. But the higher standards matter in saving lives and preventing building collapse, which also prevents injuries. Tellingly, Anchorage hospitals reported a normal day, with no dramatic upsurge in injuries from the earthquake.

Collapse of Fourth Avenue near C Street in 1964 earthquake in Anchorage. USGS photo.

One factor working in Anchorage’s favor is its relative newness as a big city, now about 300,000 population. A city of only 3,000 as late as 1940, Anchorage grew rapidly during and after World War II, still claiming only about 100,000 at the time of the 1964 earthquake. The salient result is that, between its late start as an urban center and the destruction of many older buildings in 1964, Anchorage has far fewer legacy buildings predating modern seismic construction standards than some other cities in states like California. Many California cities, including Los Angeles and Berkeley, have spent considerable sums to subsidize seismic retrofits for older structures including highly vulnerable unreinforced masonry buildings.

As an urban planner, my own expertise lies with land use and not structural engineering, so I will not elaborate on the details of building codes as if I were an expert, but the evidence is compelling. I will note one handout I found on the Anchorage city website, however, on geotechnical investigations. It concerns a requirement for a report from a geotechnical expert and inspection requirements for structures in what are known as Hazard Zones 4 and 5, which define high levels of geological susceptibility to ground failure as result of seismic shaking. The applicable handout dates to 2006, and references a June 1989 report by Shannon & Wilson, a Seattle-based engineering firm. Those dates indicate that Anchorage has been steadily at work on this problem ever since the 1964 earthquake, not wishing to repeat or continue the vulnerabilities exposed by that event.

Without delving into technical details, the bottom line is that, in the designated areas, a civil engineer with experience in geotechnical engineering must perform an investigation of the potential extent of ground movements and soil loadings on the structure proposed, and must prepare and sign a written report showing calculations, conclusions, and recommendations for how the building will be able to withstand seismic displacements without collapsing. The work must then be performed in accordance with those recommendations, and the engineer must ensure compliance through special inspections and a signed statement that his design was followed.

This approach is hardly new but is also far from universal. I learned a good deal about it in the context of municipal requirements in Utah cities around 2005 in the process of completing production of a Planning Advisory Service Report, Landslide Hazards and Planning, by the American Planning Association, with support from the U.S. Geological Survey. Such surveys cost money, but so does wanton damage from a failure to comply.

Alaska did experience problems, but not primarily with buildings. It is still far too early for a complete survey of the damage suffered by the transportation system, and the city and state need to assess the losses due to highway collapses, structural stresses on bridges, and the like. Currently, a railroad between Anchorage and Fairbanks is not functioning. There are always challenges, and every disaster is an opportunity for reassessments and lessons learned. But one clear lesson has already emerged: Building codes matter.

Jim Schwab