Awareness - Mississippi trading and high river season

Norwegian Hull Club wishes to remind its clients and members of the ongoing state of Mississippi River trading in this year's high river season.

Background 
Last year’s Mississippi high river season broke all prior records – 23 weeks above 15 feet on the Carrollton Gauge and more than 10 weeks over 16.5 feet. This coincided with a similarly record-breaking early commencement of the hurricane season.

So far, this year’s high river season has not seen the same prolonged periods in extreme high river and flood stage. On December 8 2019, the river height at Baton Rouge was almost 27 feet and rising. Flood stage is 35 feet. The corresponding river current recorded at Baton Rouge was between 3 and 3.5 knots. For comparison, the river height and current at New Orleans (Carrollton Gauge) was about 9 feet with a current of around 1.5 to 2 knots at First Street Wharf.

Challenges  for vessels
For larger and deeper draft/loaded vessels, this can create holding issues and/or associated deck machinery problems. If a vessel loses an anchor, this must be reported to the US Coast Guard, a COTP (Captain of the Port) order should follow and will likely require 'tug(s) of adequate horsepower standing by alongside until this deficiency is corrected, unless the vessel is made fast to a pier'.

'Hold position' 
On 2nd December 2019, “Marine Safety Information Bulletin (MSIB) Vol XIX Issue 091 and 091a - CARROLLTON GAUGE AT 8 FEET AND RISING” was issued, which states that 'all deep draft vessels must have three means to hold position.  An example would be two fully operational anchors and the propulsion system. Should a vessel lose an anchor or suffer a propulsion casualty, and the vessel does not have redundant capabilities available, such as aft anchors or two main engines, then a third means of holding position could be via tug assist'. It continues:

  •  NOBRA (New Orleans Baton Rouge) Pilots - recommended loading draft is as follows: 47 feet (14.3 meters) from New Orleans to Mile 180; 45 feet from Mile 180 to Mile 234.
  • Until Further Notice, the following emergency procedures set forth by the NOBRA Pilot Board of Examiners remain in effect from Mile 180 to Mile 234:
  • All vessel travel, north bound and south bound,  shall be daylight only.
  • Draft recommendation for the Mississippi River is 45 feet

 Daylight  restriction also went into effect on 24th February, implemented by NOBRA. It put the following High Water Restrictions into place: “Mile 170.0 AHP to Mile 232.2 AHP, all vessels shall be daylight only”. This daylight-only restriction, NOBRA went on to say, will remain in place until the Baton Rouge gauge has a reading of 40 feet and falling and the Carrollton Gauge reads 16 feet and falling. 

 The Lower Mississippi River Forecast Centre (LMRFC) highlighted in its bulletin of February 28  (see below) that: 

  • The Atchafalaya River will continue to rise this week;
  • Morgan City, LA is forecast to crest at 7.4ft this week;
  • The models are showing another significant rain event over the lower Ohio River by the middle of this week. The 16 day future rainfall guidance shows Cairo, IL rising again and cresting during the third week of March. Right now, the crest would be slightly higher than the crest from the week before last.  Crests would not reach the lower Mississippi River at New Orleans, LA until the first week of April.
  • The LMRFC admitted that ‘confidence is low on the eventual magnitude of the crests on the lower Ohio and lower Mississippi Rivers” due to a lack of “run to run consistency with the placement of heavy rainfall”.

    LMRFC1
  • lmrfc2

 A subsequent River Summary published on Monday March 2 by the National Weather Service forecasts that the Lower Mississippi will crest at New Orleans with near flood stage (16.9 feet) tomorrow, Wednesday March 4: https://forecast.weather.gov/product.php?site=NWS&issuedby=ORN&product=RVA&format=txt&version=1&glossary=0

 Looking ahead, the National Weather Service (NWS), has published its longer-term forecast Spring Flood Outlook #2, updated on February 28: https://www.weather.gov/dvn/2020_springfloodoutlook This update highlights the following key points: 

  • The highest concern for flooding this spring is on the Mississippi River, where the risk for major flooding is much above normal. However, confidence is low at this time in exactly how severe flooding would be at any specific location.
  • Potential for widespread minor flooding is above normal for all rivers across the area.
  • Additional heavy snowfall, a rapid snow melt, and heavy spring rains would increase the threat for more severe flooding. On the other hand, little or no additional snowfall, a prolonged snow melt, and no significant spring rains would decrease the flood threat.
  • If high soil moisture levels persist, the threat for long-duration Mississippi River flooding will increase.

     It is recommended that safety procedures and equipment should be checked and risk assessments be undertaken prior to commencement of Mississippi river trading where high currents/river conditions are anticipated.

 Norwegian Hull Club will continue to monitor the situation and provide updates as appropriate.


3. Mar. 2020