What is a Miller Type C nor’easter?

A type of nor’easter classification that is lesser known is the Miller Type C storm system, but an event of this type can be extremely impactful.

This classification refers to a specific pattern of storm development that typically occurs during the La Niña phase of the El Niño Southern Oscillation and can deliver wide-ranging impacts across the eastern half of the nation. 

The concept of Miller Type C, Miller Type D, and Miller Type E nor’easters gained increased attention in the early 2000s as climatologists studied storm system behavior and impacts.

Meteorologists classify nor’easters using the Miller classification system, named after researcher J.E. Miller, from the 1940s.

Originally, only two types of storms – Miller Type A and Miller Type B – were used for identification purposes.

Nor’easters are powerful storm systems that impact the Eastern Seaboard with a combination of northeasterly winds, heavy precipitation and coastal flooding. 

These storm systems, which typically occur in the autumn and winter months, form when cold air over the continental U.S. clashes with warm, moist air from the Gulf and the Atlantic Ocean.

The resulting events can produce blizzard conditions, hurricane-force wind gusts, severe weather and significant coastal erosion.

WHAT IS A NOR’EASTER?

What is a Miller Type C nor’easter and who does it impact?

These types of events begin as an area of low pressure in the Plains or the Rockies, which moves out of the heartland into the Tennessee and Ohio valleys.

Meanwhile, a much weaker secondary area of low pressure develops along the Gulf Coast and works inland.

The two areas eventually merge with the primary low-pressure system taking control over the Tennessee Valley and the Appalachians before exiting to the north and east.

Due to this track, a significant precipitation shield can extend from Missouri through the Ohio Valley and into major cities in the Northeast.

Given the lack of influence of the subtropical jet, widespread thunderstorm outbreaks across the South are not a typical occurrence, but locations just south of the freezing line can expect heavy rainfall.

The heavy rainfall typically occurs from the southern Tennessee Valley through the Carolinas, with a significant amount of ice along the dividing line.

Additionally, beaches along the Southeast are largely spared from coastal impacts as the storm system doesn’t bottom out until near the Delmarva Peninsula through New England.

WHAT DOES RAIN SMELL LIKE?

Historical examples of Miller Type C nor’easters

Feb. 16-18, 2003: Presidents’ Day Storm II

This powerful storm system brought four main areas of impact: heavy snow across the Plains, significant ice accretion in the southern Ohio Valley and mid-Atlantic, and widespread snowfall measured in feet along the Interstate 95 corridor, from the nation’s capital to New England.

Baltimore, Maryland, received a record-breaking 28.2 inches, while Boston, Massachusetts, saw more than 27 inches of new snowfall.

“The storm left portions of the Southeast contending with ice and sleet instead of snow, making travel conditions treacherous across large portions of the Carolinas and Georgia over the Presidents’ Day weekend,” according to a NOAA storm summary. “Airport delays across the entire Eastern Seaboard stranded thousands of travelers between Sunday, February 16, and Tuesday, February 18.”

More than two dozen deaths were either directly or indirectly attributed to the storm, which received an impact rating of 4 out of 5.

Jan. 26-28, 2004: Winter storm

A much more compact storm system, compared to the Presidents’ Day Storm of 2003, impacted the eastern U.S. in late January 2004.

The developing system had enough cold air to produce widespread ice accumulation across North Carolina, South Carolina, Georgia and Virginia. While the South grappled with dangerous icy conditions, southern New England and the Northeast were pummeled by gusty winds and heavy snowfall.

According to reports compiled by the South Carolina State Climatology Office, nearly a half-million customers in the South experienced power outages. 

The storm was responsible for at least 57 deaths from the heartland to the Eastern Seaboard.