A Year-Round Power Outage and Severe Weather Plan for a Chicago Dental Office

Picture a Wednesday afternoon in June at a practice in Orland Park. The lights dip during a crown prep, the closet battery starts to beep, the phones go silent and the front desk can no longer see who is booked at three.

This page sits inside our Chicago dental IT guide, which covers cost, staffing and software, and next to Legend's page on dental IT support in Chicago. If your office went dark this summer, or the closet froze in January, start here: the record in the sources' own words, a table of what each kind of weather breaks, the closet and cold questions, how to keep the schedule visible, a restart order, the landlord conversation and a one-page plan you can test twice a year.

How often does severe weather knock out power across Chicagoland, from Joliet to Evanston?

Often enough that a plan has to assume it. ComEd described its August 11–12, 2026 storms as "the 20th major weather event affecting ComEd customers in 2026", and the National Weather Service recorded four tornadoes inside Chicago's city limits in a single July 2024 event. In ComEd's 2026 releases, the biggest outages came from summer storms, not winter.

Every figure below is quoted from ComEd's own releases (read through the Business Wire copies syndicated on Nasdaq) or from the National Weather Service office for Chicago, with the date and a link, and each one was re-checked against its source page on October 23, 2026. Every number counts what the source counts. ComEd's unit is the customer, an electric account; it is neither a head count nor a count of dental practices, and no total here belongs to one suburb.

The 2024–2026 record, in the sources' words

The winter record is quieter on outage counts and louder on temperature. NWS Chicago wrote that "The coldest temperature in Chicago in 34 years (-23°) was recorded on the morning of January 30, 2019" (record cold, January 2019). On January 23, 2026, "Chicago's minimum wind chill observed at O'Hare Airport on the 23rd was -36°F", and "A low temperature of -11°F was also logged at O'Hare on the 23rd" (January 23–24, 2026 cold). And over January 31 to February 2, 2011, "snowfall totaled 21.2 inches officially at Chicago's O'Hare Airport, making it the third largest snowstorm on record for the city of Chicago" (the 2011 blizzard).

ComEd's releases also say it "powers the lives of more than 4 million customers across northern Illinois". At that scale a single dental suite in Evanston, Arlington Heights or Joliet is one account among millions, which is why the plan below is about what the practice controls while the grid is being repaired.

Which hazards hit a dental office in Chicago and the suburbs, and what fails first?

Each kind of Chicago weather breaks something different. Wind and tornadoes cut utility power and the internet line; lightning damages equipment through power and data cables; deep cold and summer heat push the server closet out of range; snow keeps staff away; building failures arrive without any storm. Match each hazard to the fix and its owner.

Most outage advice treats "the power went out" as one event. In a dental office the failure depends on the weather. The table sorts Chicago's hazards by what usually fails first, what should already be in place, and who owns the fix. The owner column matters most: half the rows sit with someone other than your IT provider.

Table 1: Chicago hazards × what fails in a dental office

Two patterns stand out. First, the hazards with the least warning, a tornado warning or a fast-moving derecho line, are the ones where nobody should be touching equipment, so the closet has to look after itself. Second, the owner column is mixed: a frozen pipe or a closet that bakes on a July weekend is usually a building problem before it is an IT problem, which is why the landlord section below matters as much as the battery section.

What should keep running in a Naperville or Schaumburg office when ComEd's power is out?

Very little needs to keep running, but a few things need to fail well. The server should be on a battery unit that tells it to shut itself down cleanly. The schedule and phones should be reachable from outside the building. And any generator question should be settled with the landlord and an electrician before the storm, not during it.

A useful way to think about it: you are not trying to keep treating patients through a long outage. Handpieces, compressors, vacuum, sterilizers and operatory lights draw far more power than a closet battery can supply. The goal is that nothing is damaged, no data is lost, and the practice can talk to patients while the lights are off. That holds whether the office is a medical building in Naperville, a strip center in Schaumburg or a suite above a shop in Oak Park.

The closet battery unit. A UPS (uninterruptible power supply) is a battery unit that carries equipment through short dips and gives it a chance to shut down when the outage is long. The server, the firewall and the main network switch belong on it. How it is sized is a decision for your IT provider, based on the equipment you have; this page gives no figures for it. What matters most is that the unit is set to tell the server to shut down on its own when the battery runs low, because nobody will be in the building to do it. The safe shutdown and UPS checklist covers those settings and the mistakes that corrupt a database.

Imaging computers. Acquisition PCs for sensors, pans and CBCT units often sit in operatories on wall outlets. Ask which ones hold images that have not yet reached the server. Those are the machines worth protecting first, and the ones worth checking first after the power returns. How those PCs and the server are set up in the first place is covered under dental workstation and server setup.

The generator decision. A dental office generator and UPS in Chicago are two different decisions. The battery unit lives in your closet. A generator, whether standby or portable, touches the building's electrical system, so it is a question for your landlord, the building's rules and a licensed electrician. Bring three questions to that conversation: does the building already have a generator, and what does it feed; are tenants allowed to add one; and if the practice wants some circuits covered, who designs that work. This page gives no sizing or wiring advice, and neither should your IT provider unless it is also your electrician.

The internet line. In a derecho the carrier's line often fails along with the power, because both use the same poles. A second connection from a different carrier, or a cellular backup on the firewall, keeps cloud services and remote access alive if the building still has power. Ask your provider whether a failover is in place and when it was last tested. How the closet, firewall and switches fit together is the subject of dental network design.

Phones. If your phones are hosted, calls can be forwarded to a mobile or a staff member's line while the office is dark, as long as someone can reach the settings from outside. If the phone system lives in the closet, it goes down with the power. Set forwarding rules and a weather greeting now, and test them before storm season.

Copies outside the building. Practices running Dentrix, Eaglesoft, Open Dental or Archy on a local server need a current copy of that database, and of the image store, somewhere other than the closet. Cloud services for dental offices and dental backup and disaster recovery services cover how that copy is built and restored. On price, Legend's published line is "Backup protection from $39.99 per month (storage-dependent)"; the image store usually drives the storage.

What does Chicago cold do to a server closet in Evanston, Oak Park or the Loop?

Deep cold hits a dental office twice. A closet on an outside wall, under a roof or above an unheated space can fall below the temperature its equipment tolerates, and pipes over the rack can freeze. Then the same cold, or the snow that follows, keeps staff at home. Plan for the room and for the team.

The NWS figures above are a reminder that Chicago cold is not a once-a-generation event: −23° in January 2019, a −36°F wind chill in January 2026. Most practices never think about the closet in winter because the front of the office is warm. The closet is often the one room without its own vent: a back corner, a former storage room on an exterior wall, or a space under a flat roof in a strip center in Orland Park or Arlington Heights. Brick walk-ups and mixed-use storefronts in Evanston, Oak Park and Lincoln Park can have the same problem in a back room over an unheated passage. In a Loop tower the risk is different: the room may be warm, but it sits on a building heating schedule that someone else sets.

Four checks for the winter:

1. 1. Know the closet's temperature. A simple sensor or a scheduled check tells you whether the room is drifting toward cold on a January weekend when the building's heat is set back.
2. 1. Look up. Is there a water pipe, a sprinkler line or a roof drain over the rack? If so, ask the landlord whether that line is protected from freezing, and plan where the equipment could move if it is not.
3. 1. Ask about the batteries. Battery units are affected by temperature. Ask your IT provider whether the closet's winter range suits the unit you have, and when its battery was last tested. This is a question to ask, not a reason to buy new equipment.
4. 1. Do not heat the closet with a space heater. A space heater beside a rack is a fire risk and a power draw on the same circuits. If the room needs heat, that is a heating conversation with the building.

Then the people. On days like the 2011 blizzard, the building may have power and heat, and the practice is still closed because nobody can get there. Lake-effect snow near the shore can make the same day very different in Evanston and in Naperville. A winter storm plan for a dental practice in Illinois is mostly about that: who calls the closure, and whether the front desk can work from home. The next section covers the second half.

After a cold outage. If the power has been off in deep cold, let equipment that has been sitting in a cold closet come back up to room temperature before you switch it on. Condensation on cold electronics brought into warmer air is a known hazard, so give it time rather than rushing the restart.

How does an Orland Park or Arlington Heights front desk see the schedule when the office is closed?

Decide in advance who can open the schedule from home, how they reach it, and what patients hear when they call. That means remote access set up and tested before winter, a fallback copy of the next few days' appointments, a weather greeting on the phones, and logins for the patient-texting tool stored where staff can reach them.

Go back to that June afternoon in Orland Park. The problem would not only be the power. If nobody has a way to see the afternoon's appointments from anywhere else, the team phones patients from memory and from the paper day sheet, if it was printed. Here is what to set up so the next closure is a calm afternoon of rescheduling, whether the office is in Orland Park, Arlington Heights or Lincoln Park.

• • Remote access to the practice software. If your Dentrix, Eaglesoft, Open Dental or Archy database lives on the office server, then with the office dark, a remote session into that server goes nowhere either. Ask your IT provider how the front desk would reach the schedule if the building were without power for two days: through a hosted or cloud option your software vendor offers, a copy restored somewhere else, or not at all. Get the honest answer now. Whether a given product offers a hosted option is a question for that vendor and your provider; we do not assume it here.
• • A fallback copy of the near-term schedule. A daily export or printout of the next two or three days, kept somewhere staff can reach from home, is low-tech and works when nothing else does. Treat it as patient information: store it securely and dispose of it properly.
• • A weather greeting and forwarding. Record a short closure message in advance with a placeholder for the date, and know who can switch it on from a phone.
• • The patient-texting and reminders tool. Many practices use an online service for reminders and two-way texts. Make sure at least two people know how to log in from outside the office, with multi-factor authentication on a device they carry.
• • A call list. Staff mobile numbers, the IT provider's line, the landlord's emergency contact and the carrier's business support number, on paper and in each manager's phone.

Then decide who makes the closure call and by what time. A simple rule the practice sets for itself, such as "the owner or office manager decides before the first patient is due and the greeting changes straight after", removes the scramble. Remote work is only half the answer; when someone does need to come in, remote vs onsite dental IT support explains how the two fit together.

What is the safe restart order after an outage?

Bring the office back in layers: the closet first, then the network, then the server, then the computers that depend on it, then the front desk and phones. Check each layer before the next, warm cold equipment before power-on, and run one test patient through check-in, imaging and checkout before the first real appointment.

Power often comes back in steps, with flickers. If every computer in the office switches on at once, workstations look for a server that is still starting, imaging software loses its database link, and the morning starts with error messages. Use the gate below in order, and pause at each check.

Checklist: the reopening gate for a Chicago-area office

1. 1. Confirm the power is stable. Wait until the building's power has stopped flickering. If the landlord or building engineer is restarting building systems, wait for their all-clear.
2. 1. Inspect the closet. Look for water from above, check that the room is not far colder or hotter than normal, and let equipment that sat in a cold room warm up before switching it on.
3. 1. Start the network. Carrier modem or router first, then the firewall, then the switches. Wait until the internet connection is up.
4. 1. Start the server. Let it finish starting and any disk checks it runs. Your IT provider should confirm that the practice-management database and the imaging services are running before anyone logs in.
5. 1. Start the imaging computers. On each acquisition PC, launch the imaging program your office runs (DEXIS, Vatech, Carestream, Planmeca/Romexis, Dolphin Imaging or another) and make sure it finds its image store. Check that any images captured just before the outage were saved.
6. 1. Start the front desk and operatory workstations. Log in, open the schedule and a patient chart.
7. 1. Restore the phones. Switch the greeting back, cancel forwarding and place a test call from outside.
8. 1. Run a test patient. Check a test patient in, open their chart, take or open an image, and post a test charge. If every step works, open the schedule.
9. 1. Write it down. What failed, when power returned, when the first real patient was seen. That note is the input to next season's test.

If any step fails, stop there and call your IT provider rather than working around it. The step that fails tells them where to look. For the shutdown side of the same sequence, and why a server that loses power mid-write can corrupt its database, go back to the safe shutdown and UPS checklist. Reopening a dental office after a power outage goes faster when the person running the gate has done it once in a calm rehearsal.

What belongs in your landlord conversation, from a Loop tower to a Lincoln Park walk-up?

Ask the landlord who owns the generator, the electrical riser, the roof drains over your suite and the closet's heating and cooling, and how tenants hear about planned shutdowns. The answers differ between a Loop tower, a neighborhood storefront and a suburban strip center, and they decide half the rows in Table 1.

Most practices meet the landlord over a lease and then again over a leak. Put one meeting on the calendar before the next storm season and come with a short list. The table shows how the same questions land in three common Chicago-area buildings.

Table 2: the building conversation by building type

Two things follow. If the building's heating or cooling for the closet is on a schedule, ask for an exception for that room, because equipment runs over the weekend even when the office does not. And ask for planned-shutdown notices to go to two people at the practice and to your IT provider, so a scheduled riser repair on a Saturday does not look like a storm on Monday morning.

If you are still choosing a space or planning a build-out, this is the moment to put the closet on an interior wall, away from plumbing and with its own cooling. Planning IT for a new Chicago dental practice covers closet placement at build-out.

What should a written weather plan include, and how often should you test it?

One page is enough. It names the decision-maker, the call list, the IT contact, how staff reach the schedule from home, the restart order and where the backups live. Test it twice a year: once in May before the summer storm season and once in November before deep cold, so every season starts with a plan that has just been tried.

The one-page plan

Write one plain sentence for the data line in your own terms: how much schedule and chart entry can you afford to lose, and how long can you stay closed before it costs more than prevention would? Your IT provider can turn those two answers into backup and recovery settings. Keep records as long as your compliance advisor tells you, and make sure the offsite copy is part of that plan.

Testing. A test does not need a closed office. Pick a quiet afternoon and walk through it: the decision-maker makes a mock call by the deadline, one front-desk person opens tomorrow's schedule from home, someone switches the phone greeting and back, and your IT provider restores one patient's chart and one image from the offsite copy to a different machine. Do it in May, before the June and July storms, and in November, before the cold. Write down what failed and fix it before the season.

Who runs those reviews is a choice. Some practices in Naperville or Schaumburg keep them in-house with a break-fix vendor; others hand the twice-yearly test to a monthly provider. Managed IT for Chicago dental practices compares the two, including plan reviews before storm season. To grade the backup half of this plan line by line, use the dental backup and disaster recovery checklist.

What does Legend do for Chicago-area practices when the power goes out?

Legend provides 24/7 monitoring and a staffed 24/7 helpdesk at 1-800-794-1588, so there is someone to call when your office goes dark. Its model is "onsite dispatch by appointment across served dental markets; remote-first nationwide", and it is headquartered in Dallas. Everything else on this page is what the practice and the building own.

Here is how Legend describes itself, in the approved wording:

• • Monitoring: 24/7 monitoring.
• • Calling: a staffed 24/7 helpdesk at 1-800-794-1588, one general number.
• • Who answers: In-house engineers; no outsourced first-level triage.
• • Onsite: "Onsite dispatch by appointment across served dental markets; remote-first nationwide."
• • Platforms: Legend supports the IT environment for Dentrix, Eaglesoft, Open Dental and Archy, and for DEXIS, Vatech, Carestream, Planmeca/Romexis and Dolphin Imaging.
• • Track record: Served over 3,500 practices since 2004.
• • Experience: 22+ years in dental IT (since 2004).
• • Reviews: 4.8 rating · 173 Google reviews.
• • Who is accountable: Ian Lynch — 22 years in dental IT; oversees the NOC, onsite dispatch and client technology roadmaps.

For a Midwest example of what an ongoing relationship looks like, Legend's May 2024 update on Blue Skies Pediatric Dentistry in Verona, Wisconsin celebrates Dr. Stephen Prieve's first year there and records Legend's contribution to the practice's network, technology, video entertainment and ongoing support. It is cited as a support relationship, not as a storm story. For how Legend works with practices from the Loop to the suburbs, see IT support for dental offices in Chicago, and for the wider service, dental IT support.

What to ask your IT provider before Chicago's next storm season

Use these with the provider you have today or one you are weighing. A useful answer names your closet, your equipment and a date.

If you are comparing providers for an office in Joliet, Evanston or the Loop, ask the same twelve questions of each, then read Legend's Chicago dental IT services page alongside the answers.

Sources

• • ComEd via Business Wire (Nasdaq copies): releases of June 14, 2026, August 11, 2026 and August 15, 2026. Quotes re-verified against each page on October 23, 2026.
• • National Weather Service Chicago: July 15, 2024 derecho, record cold, January 2019, January 23–24, 2026 cold and the 2011 blizzard. Quotes re-verified against each page on October 23, 2026.