On March 14-16, 1959, a major winter storm struck Iowa as a potent low pressure center moved east northeast out of Kansas into central Illinois resulting in 6 deaths and 1 injury. Precipitation began in southern Iowa as rain on the morning of the 14th then started to switch to a heavy wet snow by afternoon. The heaviest snowfall occurred overnight on the 14th-15th, with 4 inches or more falling in a wide swath from southwest to northeast across the state and some areas within that band receiving 8 to 10 inches. The highest reported storm total snowfall accumulations included 12.5 inches at New Hampton, 12.0 inches at Cresco, and 10.0 inches at Clarion, Fayette, and Fort Dodge. Winds gusting to as high as 60 mph caused severe blowing and drifting of the snow, commonly producing drifts up to 10 feet deep. There were even reports in northeastern Iowa with drifts as deep as 15 feet! Across about the southern half of the state, the heavy snow remained very wet and froze to all surfaces. As a result, thousands of trees, utility poles and lines were snapped or heavily damaged. Even after the heavy snow ended on the 15th, frozen surfaces and high winds continued to make travel impossible across most of the state. In fact, Des Moines and Dubuque authorities prohibited any travel to or from their cities. Also in Des Moines, there were 5,000 basketball fans attending the girls state tournament that spent the night in the Veterans Memorial Stadium building.
1909: A very severe blizzard struck the majority of Iowa from January 28-30, 1909. The storm began with light rain during the day on the 28th then changed to heavy rain that evening and to snow overnight. Very strong northwest winds whipped the snow into large drifts, reduced visibility to near zero, damaged homes and businesses, broke windows, and blew down thousands of windmills, utility poles, and outbuildings. Temperatures plummeted as the northwest winds kicked up with readings at Audubon plummeting from 40°F to -8°F in less than 24 hours. The highest winds occurred during the early morning hours on the 29th with gusts of 60 to 75 mph across portions of western Iowa including a peak of 72 mph at Sioux City. Thousands of livestock died from exposure as many would not face the storm to seek shelter. Many observers across about the northwestern two thirds of Iowa noted that this was the worst storm in several decades.
1991: A major winter storm pounded the upper Midwest from October 30th into November 2nd with some of the most severe effects occurring on Halloween. Snow moved into southern Iowa on the afternoon of the 30th and changed to mixed precipitation and ice on the morning of the 31st and continuing into late afternoon on November 1st. Total ice accumulations ranged from 1 to 2 inches from southwest into north central Iowa and 2 to 3 inches across southern and southeast Minnesota. In northwest Iowa, the precipitation fell as all snow. Total snow accumulations of 8 inches or more blanketed the area with 15.0 inches falling at Estherville. Stong winds produced blizzard conditions into November 2nd. The damage and hazardous travel conditions were so severe and extensive that 52 of the 99 counties in Iowa were declared disaster areas. Highways and interstates were closed across most of the state and Halloween festivities were cancelled at many locations. As the storm system moved further northeast it dumped 36.9 inches of snow at Duluth which, at the time, was the largest storm total snowfall accumulation on record in Minnesota until it was surpassed in 1994.
Extreme cold followed the crippling Halloween Storm from November 4-8, 1991. With the fresh snow pack in place, on November 4th nearly every reporting station in the state fell into the single digits and remarkably some western stations reported their earliest subzero temperatures on record, including Sioux City where the low was -3°F. Des Moines and Waterloo both established daily records with a low of 4°F. The lowest temperatures reported on the morning of the 4th included -7°F at Sioux Rapids, -9°F at Hawarden, -10°F at Sheldon, and -11°F at Cherokee. Amazingly, even colder weather would settle across Iowa a few days later with nearly the entire state falling below zero on the mornings of November 7th and 8th. On the 7th many stations set daily record lows and at numerous locations this is the earliest date on record on which the temperature has fallen below zero, including at Des Moines where the low was -3°F. The lowest reported temperatures in Iowa that morning included -12°F at Audubon, -13°F at Perry, -14°F at Le Mars, -15°F at Sheldon, -16°F at Guthrie Center, -17°F at Cherokee, and -19°F at Hawarden. On the morning of the 8th reported low temperatures included -2°F at Burlington, -8°F at Bedford and Grinnell, -11°F at Sac City, -12°F at Atlantic and Le Mars, -13°F at Cherokee and Perry, and -14°F at Guthrie Center.
Other Stories or Resources on the 1991 Halloween Winter Storm/Blizzard
http://www.weather.gov/dlh/1991halloweenblizzard (NWS WFO Duluth)
http://www.weather.gov/arx/halloween1991 (NWS WFO La Crosse)
October 25-26, 1997
A major winter storm moved into western Iowa just before midnight on October 25th and spread across about the southeastern two thirds of the state on the 26th. Two bands of heavy snow developed, one extending from Council Bluffs northeast through Boone and the other extending from northern Ringgold County northeast to around Cedar Rapids. The heaviest snowfall accumulations included 11.3 inches at Knoxville and an amazing 13.0 inches southwest of Mineola in Pottawattamie County. Electricity was lost to tens of thousands of homes and businesses in central and southern Iowa as snow laden trees fell onto power lines. This was the most significant heavy snow so early in the season in Iowa since the storm of October 16-17, 1898. On the morning of the 27th temperatures plummeted, with the aid of the fresh snow pack on the ground, bottoming out at 9 F at Atlantic and Guthrie Center which was the coldest Iowa temperature recorded so early in the season since 1972. While this system produced nearly all of the snow that fell during the month of October 1997, it was still enough to make it the third-snowiest October on record in Iowa only behind those of 1898 and 1925.
Des Moines and Waterloo Halloween Climatology
This is culmination of articles written by staff members at the National Weather Service in Des Moines, Iowa. The following links will open each blog post in a new window. All of the articles can also be found on the Weather Whisper Blog.
Fall and Winter Outlooks for Iowa – Allan Curtis, Meteorologist Intern
Iowa Summer Weather Review – Craig Cogil, Senior Meteorologist
Iowa Monthly Climate Summary – April 2016 – Ken Podrazik, Meteorologist
Iowa Monthly Climate Summary – May 2016 – Ken Podrazik, Meteorologist
Iowa Monthly Climate Summary – June 2016 – Ken Podrazik, Meteorologist
Iowa Monthly Climate Summary – July 2016 – Ken Podrazik, Meteorologist
Preparedness, Outreach, and Decision Support
NWS Partners for Iowa Heat Awareness – Kelsey Angle, Warning Coordination Meteorologist
2016 – Cooperative Observer Awards – Brad Fillbach, Cooperative Program Manager/HMT
New DSS Events Calendar Tool to Aid NWS Des Moines Partner Support – Mindy Beerends, Senior Meteorologist
Summer 2016 Central Iowa Fire Weather News – Frank Boksa, Meteorologist
Science and Technology
IRIS Comes to NWS Des Moines – Brad Small, Senior Meteorologist
Hazard Services – Improving Hazard Communication – Jeff Zogg, Senior Service Hydrologist
How Many Tornadoes can one Squall Line Produce? – Kevin Skow, Meteorologist Intern
Weather Whisper Editor: Ken Podrazik, Meteorologist
Currently, National Weather Service (NWS) forecasters must use several different software applications to compose and provide warnings, watches and advisories and related information for hazardous weather. Each tool also has different abilities to support the forecasters in their decision-making. Since each tool is uniquely designed, forecasters must learn each one and be able to quickly switch between them multiple times while on duty.
Hazard Services–an AWIPS software application presently in development–is an integral part of the NWS’s Weather-Ready Nation vision. Hazard Services represents a paradigm shift in how the NWS will communicate hazard information and aims to streamline NWS operations by integrating the functionality of the aforementioned tools into a single interface for providing timely, accurate and actionable hazard information. Within this single interface, Hazard Services will analyze data from various inputs and assist the forecaster in diagnosing and communicating the hazard information. In addition, Hazard Services will also shift the present focus on legacy text products to multiple pathways of communication such as social media, cell phones, graphics, text and XML. Thus, Hazard Services will act as a conduit for transforming leading-edge science into timely, accurate and actionable information to the end user in ways that meet their needs.
Hazard Services is also designed to be highly configurable, flexible and extensible. While work continues on the operational version for NWS local forecast offices, experimental efforts are underway to extend Hazard Services to regional and National offices such as River Forecast Centers and National Centers. An added advantage of using the same application across various levels of the NWS is the opportunity to share forecast information for consistency and collaboration which will help facilitate a unified NWS message.
Thus far, most of the Hazard Services development and testing work has involved hydrologic hazards such as river floods and flash floods. Hydrologic hazards were chosen for the initial work because local NWS offices presently use three different software applications to inform its partners and users about them—the most of any hazard. All other weather-related hazards require only one or two of the three software applications. In addition, hydrologic hazards have uniquely complicated considerations regarding watches, warnings, advisories and outlooks for them. Once the complexities of the three different software applications—as well as the inherent complexities of hydrologic hazards can be successfully addressed—then the lessons learned can be used address the other weather-related hazards.
Jeff Zogg, Senior Service Hydrologist at NWS Des Moines has been involved in Hazard Services development and testing for a few years. He also participates in the national Hazard Services Tiger and Test Teams. These teams help guide software enhancements, fixes and tests. Jeff has also participated in some of these tests. During the tests Jeff was part of a group of approximately five people who used Hazard Services as they would during an actual hazardous weather event. The tests lasted around two to three days and used weather and water data from actual past events. Testers documented software performance and stability issues—as well as enhancement suggestions—and then submitted them to the Tiger Team for prioritization on the list of items for software developers to address.
To date, 16 formal tests have occurred. Two additional tests are planned through mid-September. Within the several months, a readiness review will be conducted to determine if the process can move to the next step which involves assessment tests at four or five different sites around the country. There, Hazard Services will be put through additional rigorous but longer-term testing for a variety of different hazards. Once Hazard Services passes another readiness review after that step, it will be tested at local NWS offices. A final readiness review will then determine if and when Hazard Services will be ready to become operational and thus replace the existing software applications. Although the exact timetable of these steps is unknown, it is hoped to be completed within the next few years.
Blog post by Jeff Zogg, Senior Service Hydrologist, NWS Des Moines
National Weather Service Des Moines partnered with Iowa Homeland Security and Emergency Management for Iowa Heat Awareness from June 6-10, 2016.
Throughout the week, several partners assisted in promoting heat awareness and heat safety information. Iowa Governor Terry Branstad signed a proclamation highlighting heat safety and impacts. KCCI-TV, a CBS affiliate, conducted 6 live shots at the weather forecast office during the station’s morning broadcast on June 8th and interviewed Warning Coordination Meteorologist Kelsey Angle.
National Weather Service Des Moines partnered with the Polk County Health Department for a vehicle heat demonstration on June 9th. Hydrometeorological Technician Brad Fillbach installed a Maximum-Minimum Temperature System (MMTS) radiation shield and display unit in a GOV vehicle. The demonstration showed how quickly the temperature inside a vehicle can change in a short amount of time. Polk County Health Department Educator and Public Information Officer, Nola Aigner assisted with describing the health impacts to children and pets. The demonstration was attended by local television stations and broadcast live by UnityPoint Health through their Facebook page.
During the vehicle heat demonstration and throughout the week, the forecast office also provided updates and briefings through social media including Facebook, Twitter and Periscope. Forecaster Ken Podrazik, Meteorologist Intern Kurt Kotenberg, Meteorologist Intern Allan Curtis and Meteorologist Intern Kevin Skow provided 10 briefings through Periscope.
Blog post by Kelsey Angle, Warning Coordination Meteorologist, NWS Des Moines
The NOAA/National Weather Service’s goal of building a Weather Ready Nation is all about building relationships with our core partners including emergency managers, first responders, government officials, businesses and the general public and helping them make better decisions to save lives and property and enhance livelihoods. Communicating with everyone can be a daunting task as the National Weather Service in Des Moines has contact information for thousands of core partners and over 4,700 SKYWARN severe weather spotters.
One of our newest tools to help gather and disseminate information is called IRIS which is an acronym for Integrated Real-time Impacts and Services. This is a web based application that integrates current weather data and keeps a database of all contacts allowing our staff to call partners and spotters and disseminate Local Storm Reports quickly and easily with just a few clicks of a button. With IRIS, spotters can note their information by name and/or spotter number with their report sent out in just a matter of seconds. Under previous software, severe weather reports would need to be located with other geocoding software before being sent to the media and the world. It also has the capability of parsing out subsets of our large database and emailing those folks when necessary.
IRIS also monitors dozens of local observations alerting NWS staff of critical wind speeds and precipitation accumulations and making that information easy to disseminate with just a few clicks of a mouse. Future capabilities also include enhancing our ability to provide critical Decision Support Services to our core partners by cataloging key events and impacts important to them. Operational staff will be notified when weather elements reach critical levels.
In order for IRIS to work efficiently and optimize its information our partners and spotters need to have current location and contact information noted. If you are a member of one of these key groups and have had your address, phone number and/or email address change recently please let us know so we can update our information and database.
Blog post by Brad Small, Senior Forecaster, NWS Des Moines
Looking Back on August 31, 2014 from the Air
Residents of west-central Iowa may remember the powerful squall line that tore across the region on the evening of August 31, 2014, leaving a wide swath of wind damage from Crawford to Dallas counties. More intermittent wind damage was reported from Greene to Howard counties. In the days following the event, the NWS reviewed the wind damage reports/photos and could not conclusively distinguish any damage that could have originated from a tornado. Tornadoes produced by squall lines are oftentimes weak, transient, rain-wrapped, and sometimes embedded within broader straight-line winds, making it very difficult to differentiate tornado versus non-tornado damage in post-storm ground surveys. Mature corn crops can play a vital role in showing the unmistakable convergent path left by a tornado, and two tornadoes from August 31 were located by the author in cropland on a scientific survey on September 10, 2014 (see photo below).
However, in the weeks following the event, entire 350-km path of the squall line was imaged at ≈1-m resolution using aerial photography through the USDA National Agriculture Imagery Program. As stated earlier, the predominantly flat, mature agricultural land cover of central Iowa provided an excellent medium on which to document all scales of wind phenomena. The imagery (discovered and analyzed during the last 6-8 months) revealed an astounding 111 discrete damage tracks that could have originated from a tornado. These tracks ranged in length from a mere 130 m to nearly 18 km. Given the uniqueness of this dataset and the high likelihood that some of these tracks were from surface vortices that did not meet the formal definition of a tornado (a circulation reaching to cloud-base), a probabilistic testing scheme was developed. This test weighted various track characteristics (length, strength, circulation nature, and damage) and radar data to determine which tracks had the highest chance of being from a tornado. Using this test, 35 of the 111 tracks (31%) were classified as tornadoes. Four of the tracks were rated EF-1 using the aerial data and the rest as EF-0.
The sheer number of damage paths revealed by this dataset is truly unprecedented. No other study has ever uncovered so many tracks produced by a single squall line. The aerial data also showed two tornadoes merging into one single entity just northeast of Stratford (see image below), one of only four mergers ever documented and the first with tornadoes from a squall line. This event unearthed far more questions than answers, not only concerning how these tornadoes formed, but also with how the NWS should handle these types of situations. Using hypothetical tornado warnings that would have encompassed the area most at risk to tornadoes on August 31, it was calculated that only 0.24% of the warning area would be impacted by a tornado. Should the NWS be issuing tornado warnings for these low-impact, short-lived tornadoes that would rarely cause damage greater than EF-0/EF-1? Is it worth false alarming over 99.8% of the warning area to try to capture these fleeting tornadoes that would likely go undocumented? In addition, how should the NWS document such tornadoes for historical records? Since aerial data will not be available for all events, a bias would be introduced into Storm Data. The August 31, 2014 squall line exemplifies this bias to the extreme. To put this event in context, the 35 tornadoes from August 31, 2014 would rank as the single greatest tornado outbreak in Iowa history, an outbreak that no one has ever heard of! These questions and more will need to be addressed by the NWS over the coming years not only as the organization moves towards impact-based warnings, but also as the availability and accessibility of aerial/satellite imagery datasets increase. This case highlights the incredible utility of aerial and satellite datasets for storm surveying, a benefit that the NWS will hopefully capitalize on in the years to come.