Australian authorities on Tuesday released a video to help families of passengers of the missing Malaysia Airlines Flight MH370 understand the challenges involved in the ongoing, months-long search for the missing jet. The four-minute long video was posted by the Joint Agency Coordination Centre (JACC) on YouTube.

The video reveals details about the search area, which is now concentrated along the seventh arc in the southern Indian Ocean. The arc is described as “a thin but long line that includes all the possible points where the last known communication between the aircraft and the communication satellite could have taken place.” The video also says that experts have been constantly analyzing all available data in an attempt to pinpoint the plane's location.

“Searching for MH370 is a complicated task. The search area is a long way from land. The water is very deep and the sea floor is largely uncharted,” the JACC, which is coordinating the current search from Australia, says, in the video.

The agency also points out that Australia, Malaysia and China are all contributing to the ongoing search for Flight MH370, which disappeared on March 8 with 239 people on board, triggering an unprecedented and expensive international search operation for the Boeing 777.

The agency also reveals details of how the sea floor looks in this remote portion of the southern Indian Ocean. Authorities also say that a detailed bathymetric survey of the sea floor was commissioned because very little information is available about the search area. So far, an area of over 1,158 square miles of the ocean floor has been mapped.

“The bathymetric operation in the search area has identified that the waters are extremely deep, up to six kilometers (about 3.7 miles) in some areas,” JACC said. “Daylight can only penetrate a very short distance and, on the deep sea floor, there is no light to see by.”

The video also provides details about the survey vessels, including GO Phoenix, Fugro Discovery and Fugro Equator, which are part of the latest phase of the search, which resumed in September, following a four-month long break. JACC said in a statement on Wednesday that nearly 2,664 square miles of the sea floor has been searched so far, without any positive clues as to the whereabouts of the plane.

“The search area is very large… until now little detail is known about the shape and depth of the ocean floor. Gathering this information helps ensure a thorough and safe search of the sea floor,” JACC said in the video.

Here is the video of the search for Flight MH370.