Tornado Alerts, Phone Call Warnings & Severe Weather Questions — Answered

What weather app calls you during a tornado?

VORTEX Pro places an automated phone call when the NWS issues a tornado warning for a location you have saved; it rings through Do Not Disturb if you add the number as an Emergency Bypass (iPhone) or priority (Android) contact.

The Pro plan ($4.99/month or $39.99/year) includes phone call alerts for:

• Tornado warnings at any saved location
• Flash flood warnings at any saved location
• Proximity alerts when warnings are issued in adjacent counties

A 14-day free trial is available if you want to test it before subscribing.

Can an app phone me during a tornado warning?

Yes — VORTEX Pro places a real phone call when a tornado warning is issued for your saved location, checking your location against the actual NWS warning polygon.

How do I get a phone call for severe weather alerts?

Subscribe to VORTEX Pro, set your locations, and VORTEX calls you when a tornado or flash flood warning is issued for your area. A few other services also place severe-weather warning calls; VORTEX additionally keeps the free government WEA channel visible so you are covered before you subscribe.

Does VORTEX call for flash flood warnings?

Yes — VORTEX Pro calls for both tornado and flash flood warnings at your saved locations, gated to a tight radius so it only calls when the threat is close.

How do I get tornado alerts while sleeping at night?

Most weather apps send push notifications, which are silenced by Do Not Disturb mode at night. To get tornado alerts that actually wake you up, you need either a NOAA weather radio or an app that calls your phone.

VORTEX Pro calls your phone directly when a tornado warning is issued for your location. Phone calls can bypass Do Not Disturb once you enable Emergency Bypass (iPhone) or mark the number a priority contact (Android), helping you wake up and take shelter.

This is especially important because nighttime tornadoes are 2.5 times more deadly than daytime tornadoes, largely because people are asleep when they strike. The EF-4 tornadoes that struck overnight in Mayfield, Kentucky (December 2021) and across the Southeast repeatedly have shown how critical reliable nighttime alerting is.

Do tornado sirens work when you are inside your house?

No. Outdoor tornado sirens are designed to alert people who are outside, not inside. They are not intended to be heard indoors, especially in:

• Well-insulated or newer homes
• Storms with heavy rain or thunder
• Homes with windows closed and air conditioning running
• While sleeping (even if audible)

Many people are surprised to learn sirens are an outdoor-only warning system. For indoor alerting you need a NOAA weather radio, Wireless Emergency Alerts (WEA) on your phone, or a weather app like VORTEX. Sirens should never be your primary alert method — they should be a backup layer at best.

How do I set up Emergency Bypass on iPhone for tornado alerts?

Emergency Bypass is an iPhone feature that lets a specific contact ring and vibrate even when Do Not Disturb, Silent mode, or a Focus is active. It's the most reliable way to ensure VORTEX tornado alert calls wake you up at night.

The VORTEX alert number is (479) 552-5858. Setup steps:

1. Save the number as a contact — e.g. VORTEX Alert
2. Open the contact → tap Edit
3. Tap Ringtone → toggle Emergency Bypass on
4. Tap Vibration → toggle Emergency Bypass on there as well
5. Tap Done

With both enabled, the call will ring and vibrate regardless of Do Not Disturb, Silent mode, or any Focus setting.

Optional — lock your ring volume: go to Settings → Sounds & Haptics and disable "Change with Buttons" so your ringer can't be turned down by accident. Note that this affects all incoming calls, not just VORTEX.

How do I let tornado alert calls ring through Do Not Disturb on Android?

Android doesn't have an Emergency Bypass feature like iPhone, but you can allow specific contacts to ring through Do Not Disturb.

First, save the VORTEX alert number (479) 552-5858 as a contact named VORTEX Alert and star/favorite the contact by tapping the ★ icon.

Stock Android (Pixel and similar):

1. Settings → Sound → Do Not Disturb → Allow exceptions
2. Enable Calls from starred contacts (or pick the VORTEX Alert contact directly if your Android version supports it)

Samsung: Settings → Notifications → Do Not Disturb → Allow exceptions → Calls → set to Favourite contacts or All contacts.

Xiaomi / OnePlus / other OEMs: look for an Allow exceptions or Priority section under Sound or Notifications — the naming varies but the concept is the same.

How do I enable Critical Alerts and keep Android from killing push notifications?

VORTEX push notifications (risk score alerts, pressure drop alerts, non-call NWS alerts) are delivered via ntfy, a free open-source notification service. To ensure they break through Do Not Disturb and silent mode:

iPhone — Critical Alerts: go to Settings → ntfy → Notifications, allow notifications, and enable Critical Alerts if prompted. Critical Alerts bypass Do Not Disturb and Focus modes entirely for severe weather.

Android — Battery Optimization: some manufacturers (Samsung, Xiaomi, OnePlus, Huawei) aggressively restrict background apps, which can prevent push notifications from arriving. Go to Settings → Battery → Battery Optimization, find the ntfy app, and set it to Unrestricted or Don't optimize.

Also verify notifications are allowed: Settings → Apps → ntfy → Notifications with all categories enabled.

Phone call alerts are separate from push notifications — those use Emergency Bypass (iPhone) or Do Not Disturb exceptions (Android), described in the two questions above.

What is the difference between a tornado watch and a tornado warning?

A tornado watch means conditions are favorable for tornadoes to develop in your area over the next several hours. Stay alert and monitor the weather — but no tornado has been spotted yet. Watches cover large areas (multiple counties or states) and typically last for several hours.

A tornado warning means a tornado has been spotted or indicated by radar in your immediate area. Take shelter immediately in an interior room on the lowest floor, away from windows. Warnings are location-specific (usually polygon-shaped) and typically last 30–60 minutes.

VORTEX phone calls are triggered by warnings, not watches. Watches are shown on the map and in push notifications but do not trigger a phone call — otherwise your phone would ring dozens of times per severe weather season.

What is the best tornado warning app in 2026?

The best tornado warning app depends on what features matter most to you:

• If you need to be woken up by alerts, choose an app that calls your phone — VORTEX is built specifically for this.
• If you want free alerts, the National Weather Service's Wireless Emergency Alerts (WEA) are sent to all phones automatically but can be silenced by Do Not Disturb.
• If you want comprehensive severe weather intelligence including risk scoring, live radar, and tornado phone calls, VORTEX costs $4.99/month.

Compare this to outdoor-only tornado sirens (useless indoors) or a NOAA weather radio (requires a dedicated device and alerts for entire counties, often unnecessarily). Most storm-aware people use multiple layers: a weather radio as backup, WEA on their phone, and a dedicated alert app like VORTEX.

How much does VORTEX cost?

VORTEX has a free tier that includes:

• Live NEXRAD radar with storm tracking
• NASA global precipitation (IMERG)
• GOES-East satellite cloud-top imagery
• Real-time severe weather risk scoring (0–100)
• NWS warning & watch polygons on the map
• Past Tornadoes — SPC storm-report points, April 2025 to present
• Past Warnings — recent NWS tornado-warning polygon archive

The Pro plan costs $4.99/month or $39.99/year (save 33%) and adds:

• Phone call alerts for tornado & flash flood warnings
• Proximity alert calls for storms tracking toward you
• Push notifications for all NWS warning types
• Risk score & rapid pressure drop push alerts
• Multi-city monitoring (up to 3 alert-enabled locations)
• Earthquake (USGS) & wildfire (NIFC) map overlays
• Prewarmed weather cache for instant load
• Alert history (30 days)
• Philips Hue smart light integration (beta)

A 14-day free trial of Pro is available — a payment method is required to start the trial, but you won't be charged until the 14 days end. No credit card required to use the free tier.

What is a tornado risk score?

A tornado risk score is a numerical assessment of severe weather conditions used to gauge how favorable the atmosphere is for tornado development. VORTEX calculates its risk score from six atmospheric factors:

• CAPE — Convective Available Potential Energy (storm fuel)
• Storm-Relative Helicity — rotational energy in the atmosphere
• Wind Shear — how wind changes with altitude
• Relative Humidity — moisture content
• Dewpoint — low-level moisture availability
• Lifted Index — atmospheric instability

Scores range from 0 (no risk) to 100 (extreme risk). The score is also capped by the SPC Day 1 tornado outlook — a hot but quiet summer airmass outside any SPC tornado area can't read as extreme tornado risk. This gives you a quick read on conditions hours before storms actually develop — useful for deciding whether to cancel outdoor plans or stay near shelter. See the Risk Score documentation for how each factor is weighted.

How often will I get Risk Score alerts during a long severe weather event?

VORTEX fires one Risk Score push when the score crosses your configured threshold, then stays quiet — even if conditions stay above threshold for hours. You'll get a fresh alert when:

• The score dips at least 5 points below your threshold and crosses back above it — a genuinely new threat episode
• 6 hours have passed since the last alert and conditions remain dangerous — a "still elevated" reminder so a missed or dismissed push doesn't leave you blind during a sustained event

Alerts are edge-triggered — each one maps to a real change in conditions rather than a repeating timer. That means you get a push when something genuinely shifts, not a steady drip of reminders while the atmosphere stays primed for hours.

Note: this rule is independent of NWS warnings. Tornado warnings and Flash Flood Warnings call your phone via Twilio when issued and follow their own rules — see the alert types overview.

How many phone calls will VORTEX make during a major outbreak?

VORTEX places one phone call per unique tornado or flash flood warning that affects your home location, an alert-enabled city, or your proximity radius. There is no daily call limit — a real outbreak that produces 8 separate warnings will result in 8 calls.

Two important dedup rules keep this from getting noisy:

• One call per warning, not per update. If the NWS extends, updates, or re-issues the same VTEC warning, you won't be called again for it.
• One call when overlapping locations are in the same warning. If your home AND a pinned city are both inside the same warning polygon, you get one call — not two.

In practice, average users see 0–3 calls per day even on active severe weather days. The cases where you'd see many calls in a short window:

• Multiple unrelated warnings hitting your watch areas in a few hours (e.g. tornado warning at home + flash flood warning at a pinned city + tornado warning passing within proximity radius)
• Storm chasing by changing your home location into multiple counties under active warnings — this is what dev/admin testing looks like, not normal use

If a single account exceeds 20 successful calls in 24 hours, an internal admin alert fires for review. We previously had a hard 10-call/24h cap, but it was removed in April 2026 after a real proximity tornado warning got suppressed because earlier flash-flood calls had filled the daily window. The new behavior favors emergencies over arbitrary ceilings.

How do tornado alerts work on iPhone and Android?

Both iPhone and Android devices receive free government Wireless Emergency Alerts (WEA) for tornado warnings automatically when connected to a cellular network. These sound a loud alarm and display a notification.

However, WEA can be silenced by:

• Do Not Disturb mode
• Airplane mode
• Poor cellular signal
• Phone turned off or muted

For more reliable alerting, apps like VORTEX Pro place an actual phone call to your device when a tornado warning is issued — phone calls can bypass Do Not Disturb once you enable Emergency Bypass (iPhone) or mark the number a priority contact (Android). On Android, you may need to disable battery optimization for VORTEX in your system settings to ensure background alerts work reliably.

Can deaf and hard-of-hearing people get tornado alerts?

Outdoor tornado sirens are useless for deaf and hard-of-hearing people. Several options exist:

• NOAA weather radios with accessory strobe lights or bed shakers
• Wireless Emergency Alerts (WEA) which vibrate the phone
• Weather apps with push notifications
• VORTEX Pro phone calls which trigger the phone's continuous vibration pattern until answered

A phone call vibrates much more insistently than a push notification — combined with a vibrating smartwatch, this can reliably wake sleeping users. Contact [email protected] if you need help configuring VORTEX for accessibility.

What should I do if a tornado warning is issued for my area?

Take shelter immediately.

• Go to the lowest floor of a sturdy building
• Into an interior room with no windows — a bathroom, closet, or hallway
• Cover yourself with a mattress, heavy blankets, or a helmet to protect from flying debris

If you are in a mobile home, vehicle, or RV, leave immediately and seek a sturdy building — these structures offer virtually no protection. If no shelter is available and you cannot outrun the storm, lie flat in a ditch or low spot and cover your head.

Do not try to outrun a tornado in a vehicle in urban areas. Tornadoes can travel 60+ mph and change direction unpredictably.

What areas does VORTEX cover?

VORTEX's core alerting is built around the entire United States, including:

• Tornado Alley: Oklahoma, Kansas, Texas, Nebraska, South Dakota, Iowa, Missouri
• Dixie Alley: Arkansas, Louisiana, Mississippi, Alabama, Tennessee, Georgia
• All other US states and territories

NWS tornado warnings, flash flood warnings, phone call alerts, the live NEXRAD radar layer, and the NIFC wildfire overlay are US-only. The map itself is global — you can pan anywhere in the world and see NASA GPM IMERG precipitation (50°N–50°S), GOES-East satellite cloud-top imagery (Americas), and USGS earthquakes (worldwide). See the "Does Vortex work outside the US?" question below for the full coverage breakdown.

Does Vortex work outside the US?

The map works globally, but alerting is US-only. Here's exactly what's available internationally:

✅ Interactive global map — pan and zoom anywhere
✅ Global precipitation (IMERG) — NASA's satellite-derived precipitation between 50°N and 50°S. Works over oceans, deserts, and countries without radar networks. ~3.5 hour source latency.
✅ Satellite cloud-top imagery (IR) — GOES-East Band 13 Clean Infrared, covering the Americas and adjacent oceans. 10-minute updates.
✅ Earthquakes (Pro) — USGS reports earthquakes worldwide

❌ NWS warnings & watches — US only. No coverage in Canada, Mexico, or outside the US.
❌ Phone call alerts — US only. Our alerting infrastructure only subscribes to NWS warning feeds.
❌ NEXRAD live radar — US-territory only (continental US, Alaska, Hawaii, PR/USVI, Guam).
❌ Wildfire overlay — US-only (sourced from NIFC, which only tracks US incidents).

If you travel internationally, the map still works — you'll see precipitation, satellite clouds, and earthquakes — but you won't get phone calls or push notifications for severe weather abroad.

How fast are VORTEX tornado alerts?

Best case: just a few seconds. When the NWS issues a warning for your location, VORTEX detects it and places your call. On a good day that entire chain completes in under 10 seconds.

Worst case: around a minute or so, depending on exactly when the warning is published relative to our monitoring cycle. Either way it's comparable to or faster than Wireless Emergency Alerts and faster than most weather TV broadcasts.

Can I get tornado alerts for multiple locations?

Yes. VORTEX Pro supports up to 3 alert-enabled cities plus your home location, for a total of 4 monitored locations. This is useful if you want to:

• Monitor severe weather for family members in other cities
• Track a second home or cabin
• Stay informed about your workplace while traveling
• Watch weather for elderly parents in another state

You can pin up to 10 cities on the map for visual monitoring, but only 4 locations can have active background alerting at once.

How do I prepare for tornado season?

Prepare for tornado season by:

• Identifying your safest shelter location (basement, interior bathroom, or closet on the lowest floor)
• Keeping a NOAA weather radio with battery backup
• Practicing a tornado drill with your family
• Assembling an emergency kit: water, flashlight, first aid, sturdy shoes, helmets
• Knowing the difference between a watch and warning
• Signing up for multiple alert methods including phone apps like VORTEX
• Knowing your county name — many alerts reference counties rather than cities

Tornado Alley peak season is typically April through June. Dixie Alley has two peak seasons: spring (March–May) and fall (November). Know your region.

Is a NOAA weather radio still worth buying in 2026?

Yes, a NOAA weather radio is still a valuable layer of redundancy, especially during power outages when cellular networks may fail. However, weather radios have drawbacks:

• They only work within range of a NOAA transmitter
• They alert for entire counties, often causing unnecessary 3 AM alarms for warnings 50 miles away
• They require a dedicated device

Many people today use a combination of a weather radio as backup plus a phone-based alert system like VORTEX Pro for location-specific phone call alerts. Layers of warning save lives — no single alert method is perfect.

Does VORTEX work for flash floods and other severe weather?

Yes. VORTEX Pro places phone calls for both tornado warnings and flash flood warnings — flash floods kill more people annually in the US than tornadoes.

VORTEX also provides push notifications for:

• Severe thunderstorm warnings
• Winter storm warnings
• Fire weather warnings
• All other NWS alert types

Pro users also get earthquake (via USGS) and active wildfire (via NIFC) visual overlays on the map, so VORTEX functions as an all-hazards severe weather intelligence platform, not just tornado-focused.

What phone number will call me from VORTEX?

All VORTEX alert calls come from (479) 552-5858. Save it in your contacts as "VORTEX Alert" — this ensures the call rings through Do Not Disturb (with Emergency Bypass enabled on iPhone or Favourite-contact exceptions on Android) and so you immediately recognize it as a real alert.

VORTEX uses Twilio to place the call. Each call announces:

• The type of warning (tornado, flash flood, or proximity alert)
• The affected location
• Repeats key information twice within the same call so you hear the full message even if you pick up partway through

See the help page for step-by-step Emergency Bypass setup on iPhone and Android.

Why do tornadoes happen at night in the South more than the Plains?

In the Great Plains (Tornado Alley proper), storms are typically driven by the afternoon heating cycle, producing most tornadoes between 3 PM and 9 PM.

In the Southeast (Dixie Alley — Mississippi, Alabama, Arkansas, Louisiana, Tennessee, Georgia), storms are often fueled by Gulf of Mexico moisture and low-level jet streams that peak overnight. This means Dixie Alley sees a disproportionate number of overnight tornadoes, which are significantly more deadly because people are asleep.

If you live in Dixie Alley, reliable nighttime alerting — like VORTEX phone calls — is especially critical. Statistically, if you live in Alabama or Mississippi, you are far more likely to be hit by a tornado while asleep than while awake.

What are "Past Tornadoes" and "Past Warnings" on the map?

These are two free-tier historical layers you can toggle from the Map Layers panel:

• Past Tornadoes — Reported tornado touchdowns from SPC's daily storm reports, covering April 2025 to present. SPC's rating field is not upgraded after publication, so a dot carries an EF rating only when an NWS damage survey result appears in the report text (marked as survey-derived); the rest are labelled Preliminary. Pan to your area to see the tornado reports near you.
• Past Warnings — the NWS tornado-warning polygon archive. Shows every warned area over the recent window so you can see how often NWS has issued warnings for your neighborhood.

Both are useful for risk context: "has my town been hit before?" and "how often does this area get warned?" Together with the per-city tornado-history pages (see next question), they're how VORTEX surfaces historical severe-weather context that most apps hide behind paywalls or don't show at all.

What are Storm Briefings and the City Tornado History pages?

Storm Briefings (at /blog) are daily weather write-ups covering the active severe weather threat, recent storm recaps, and explainers. Published daily; written to be fact-checked against SPC outlooks and NWS storm reports before they go live.

City Tornado History (at /tornadoes) is a set of per-city landing pages with the full tornado history of a location — total count, deadliest events, worst years, and a map of every recorded touchdown nearby. Great for local risk awareness; useful to share with family or post-incident coverage.

Both are free and available without an account.

How do VORTEX push notifications work?

VORTEX delivers background push notifications through ntfy.sh — an open, privacy-respecting push service. Setup (one-time):

1. Install the free ntfy app from the App Store / Play Store.
2. In ntfy, tap + Subscribe to topic and create a private channel (any random name — this becomes your channel URL).
3. In VORTEX, go to Settings → Integrations and paste your ntfy channel URL.
4. On iPhone, enable Critical Alerts for ntfy in iOS Settings → ntfy → Notifications.
5. On Android, set the ntfy app's battery optimization to "Unrestricted" so alerts reliably wake the device.

Push notifications are Pro-only. The full ntfy setup guide has screenshots.

How accurate are VORTEX's tornado projections?

We publish our projection accuracy openly at vortexintel.app/accuracy — as far as we know, no other severe-weather app does this. The page is a live scoreboard computed from real tornado warnings over the trailing 90 days.

The six numbers we surface:

• Typical miss (P50, 0–15 min lead) — half of short-lead projections land closer than this.
• Persistence skill — what fraction of our projections beat a "do nothing" baseline (leave the dot where it was). If this drops below 50%, the projection is actively hurting.
• Honest limits (P95, 15–30 min lead) — the worst-5% miss at longer lead. This is what we can't claim to do well.
• Catastrophic miss rate — fraction missing by more than 10 miles. Usually storms that changed direction sharply.
• 14-day trend — short-lead P50 over the last two weeks vs. the two weeks before.
• Sample size — how many scored projections this window includes.

Cards below N=30 are dimmed as "low sample" — they're included for transparency, not marketing. We don't publish projections beyond 30 minutes because the P95 widens past 25 miles at those lead times, which isn't useful for safety planning.

Technical detail: we use dead-reckoning projection from the NWS-reported motion in eventMotionDescription. Errors compound with every minute of lead time. If the NWS forecaster re-issues with a new motion fix, we look wrong even when the math was right — that real-world source of error is included in these numbers, not filtered out.

How does VORTEX compare to the Storm Prediction Center website?

The Storm Prediction Center (SPC) is a government agency that issues severe weather outlooks and watches for the entire US — it is the authoritative source for severe weather forecasting.

VORTEX consumes SPC data and NWS alerts and delivers them to users with phone calls, push notifications, and personalized location-based risk scoring. Think of SPC as the forecaster and VORTEX as the delivery system that makes sure you actually receive critical alerts in time to act — particularly at night when other alert methods may fail.

Most serious weather watchers bookmark both: spc.noaa.gov for outlooks and vortexintel.app for location-specific real-time alerts.