The opioid addiction crisis rampaging across the country hit my home city of Cincinnati with a terrible fury last summer. In one sweltering week in August, our first responders were deluged with emergency calls to deal with a record 174 overdoses of heroin. Worse, this heroin often was (and still is) laced with carfentanil, a synthetic opioid designed to render elephants unconscious.

The sad reality, of course, is that Cincinnati is by no means unique. Our 2016 spike was just one piece of a scourge afflicting cities, towns and rural areas across the country. These heart-breaking maps of American deaths due to overdose, created by our data-platform partner Socrata, illustrate the vast scope and rapid growth of the epidemic since 2002. Our efforts to reverse this expansion require the involvement not only of first responders but of public and private institutions across our communities.

Before we can respond effectively, however, we need to know just what we're dealing with. We need data, presented in an analytical way that helps us target our limited resources. So we built an application for it. Deployed to the web with a mobile-friendly interface, the "Heroin Overdoses in Cincinnati" page is an integral part of our city's interactive dashboard. Informally, it goes by another name: the Heroin Tracker.

Automatically updated nightly from our 911 call and public safety dispatch database, the Heroin Tracker displays overdoses by day and time, neighborhood and ambulance transport (if any), along with total overdose rates across a 13-month span. While still an early version, the Tracker is already surfacing potentially useful insights. For example, where one might expect opiate overdoses to spike late at night, we learned that most occur during the afternoon and early evening. (Mysteriously, the very highest number of overdoses happens Wednesdays around 6 p.m.)

The data is also precise enough for practical action. Every day, dozens of public-safety and health-department officials, along with Talbert House (a fantastic nonprofit offering substance-abuse treatment and other services) check the Heroin Tracker. It helps them plan more targeted patrols in neighborhoods with the most serious overdose hotspots and anticipate overdose spikes based on previous trends.

We may already be seeing positive results. In 2016, despite the August spike, we actually saw fewer deaths due to overdose than in 2015. Experts attribute this in part to prompt applications of Narcan for reversing overdoses. That's to the great credit of our first responders, who stand ready to provide the proper dosage when an emergency call comes. And this, in part, is due to our Tracker, pointing them to places where and when their help is most likely needed -- helping them arrive before it's too late.

Reducing the number of deaths from opioid overdoses is just one part of the picture. We also need to do what we can to reduce and prevent overdoses. While heroin fatalities are down in Cincinnati, our Tracker recently recorded a disturbing increase in overdoses: 156 in April, compared to 94 in the same month in 2016. In future updates, we plan to complete the loop, tracking patients sent to the hospital by the treatments they receive and how many have broken free of addiction (with all patient data anonymized according to our privacy guidelines).

An even greater update would scale the Heroin Tracker beyond Cincinnati, into other localities struggling with addiction. Building on what we've learned, we might begin to reverse overdose trends. Sharing our data across cities and states, we could better target treatment and plan preemptive action that might prevent local epidemics before they start. While no one app can solve such a major public-health problem, it can become a catalyst in the overall solution.

The greatest challenge isn't monetary but cultural. Something like the Heroin Tracker needs buy-in across a city or county, from elected officials to law enforcement to health and community services. And that requires a collective willingness to share painful facts with each other and with the public. In the end, however, sharing data about opiate overdoses is functionally no different than sharing data about any other civic challenge. The act itself becomes a motivation to take action.