High Impact Weather Briefing #4: Catastrophic and Life Threatening Flash Flooding Likely Over The Next 72 Hours. Comprehensive Timeline Attached

Overview:

Hurricane Helene is forecast to impact the Western North Carolina Foothills over the next several days, bringing significant risks of flooding, damaging winds, and severe weather. This briefing outlines key information to help residents prepare and stay safe during this weather event.

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Key Messages:

1. Helene is Expected to Strengthen: The storm will intensify as it moves through the Gulf of Mexico, likely reaching hurricane strength before impacting the southeastern United States, including Western North Carolina.
2. High Risk of Flash Flooding: Widespread heavy rainfall is anticipated from Wednesday through Friday. Rainfall totals could reach 5-7 inches across the region, with locally higher amounts up to 12 inches possible (locally higher in south facing slopes), especially along the eastern slopes and foothills. This will likely result in flash flooding, particularly in areas prone to poor drainage.
3. Severe Weather Threat: Helene brings an increased risk of severe weather, including damaging winds and tornadoes. The highest risk period for severe weather is pre-dawn Friday morning.
4. Widespread Power Outages Possible: Strong tropical storm-force winds are expected, with gusts reaching up to 40-50 mph in some areas. Residents should prepare for potential power outages due to downed trees and power lines.
5. Flooding Timeline: The greatest risk of flooding will occur late Wednesday through Friday, with heavy rain bands moving through the area, especially during overnight hours.

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Potential Hazards:

1. Flooding Risk: Rare and Catastrophic Flood Possible
   • Significant life threatening flash flooding and mudslides are possible, especially along east and south facing slopes, low-lying areas, creeks, and streams.
   • Flood Watches are in effect and warnings are expected
2. Tornado Risk: Medium
   • Tornadoes are possible, particularly on Thursday night into Friday morning. Be prepared to take shelter quickly.
3. Tropical Storm Winds: High
   • Strong winds exceeding 50mph are expected, which could result in downed trees and power lines.

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Hazard Timelines:

• Wednesday:
  Flooding risk begins to increase throughout the evening, peaking in the evening hours.
  
• Wednesday Night:
  The highest flooding risk, with heavy rainfall expected through the overnight hours.
  Wind risks remain low.
• Thursday:
  Continued heavy rainfall with an elevated risk of flash flooding in the afternoon and evening.
  Wind risks will remain medium, with gusts potentially causing localized damage.
• Thursday Night:
  Extreme flooding risk as Helene moves closer. Tornado potential increases, with the peak wind threat late in the night into Friday Morning
• Friday:
  Torrential rainfall continues, with flash flooding and wind damage possible into the afternoon.
  Gradual improvement expected by evening as the storm system moves northward.

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Forecast Rainfall Totals (Tuesday – Friday Night):

• 5-7 Inches: Most areas across the foothills.
• 7-10 Inches: Higher terrain and eastern slopes, with potential localized amounts exceeding 12 inches.

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Wind Forecast (Thursday Evening – Friday Night):

• Gusts of 30-50 mph are expected, with stronger gusts in higher elevations.
• Residents should secure outdoor objects and prepare for power outages.

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Flash Flood Potential Map Summaries:

• Tuesday: Low to Medium flood risk with potential localized flash flooding due to slow-moving thunderstorms.
• Wednesday: Elevated flood risk as moisture increases across Polk, Rutherford, McDowell, Burke, and Caldwell counties.
• Thursday: High to Extreme flood risk, particularly across eastern slopes and adjacent foothills.
• Friday: Continued extreme flood potential, especially in southern and eastern slopes.
• Saturday: No additional flooding expected

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Actions to Take:

• Prepare Now: Ensure you have emergency supplies, including food, water, and medications. Charge devices and have backup power options if possible.
• Stay Informed: Monitor local weather updates through trusted news sources and the Foothills Action Network.
• Flood Safety: Do not attempt to drive through flooded roadways. Turn around, don’t drown.
• Severe Weather Preparedness: Be ready to take shelter in a safe location, especially during overnight hours when tornadoes are possible.
• Wind Safety: Secure loose items outside and avoid parking vehicles under trees.

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Conclusion:

This is an evolving weather situation with high impacts expected. Residents of Western North Carolina Foothills should remain vigilant and prepared for catastrophic life-threatening flooding, severe weather, and power outages over the next few days. Now is the time to take action to protect yourself, your family, and your property.